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<p class="MsoNormal"><span style="color:#203864;mso-style-textfill-fill-color:#203864;mso-style-textfill-fill-alpha:100.0%">Hello,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#203864;mso-style-textfill-fill-color:#203864;mso-style-textfill-fill-alpha:100.0%"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#203864;mso-style-textfill-fill-color:#203864;mso-style-textfill-fill-alpha:100.0%">A Webkit exploit was reported where WebKit implementation was vulnerable to ROP(return oriented programming) attacks. Here are the details:
<a href="https://www.exploit-db.com/exploits/28081/"><span style="color:#033160;mso-style-textfill-fill-color:#033160;mso-style-textfill-fill-alpha:100.0%">https://www.exploit-db.com/exploits/28081/</span></a>.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#203864;mso-style-textfill-fill-color:#203864;mso-style-textfill-fill-alpha:100.0%">However, we are interested in knowing which revision of WebKit has the fix for resolving this vulnerability.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#203864;mso-style-textfill-fill-color:#203864;mso-style-textfill-fill-alpha:100.0%"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#203864;mso-style-textfill-fill-color:#203864;mso-style-textfill-fill-alpha:100.0%">Digging more info, we found that the exploit was due to an heap buffer overflow issue in JavaScriptCore JSArray::Sort() method.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#203864;mso-style-textfill-fill-color:#203864;mso-style-textfill-fill-alpha:100.0%">Details:<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.55pt"><span style="font-size:10.5pt;font-family:Consolas;color:#666666"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height:11.55pt"><span style="font-size:10.0pt;font-family:Consolas;color:#666666;background:#FAF6E1">The heap memory buffer overflow vulnerability exists within the WebKit's
</span><span style="font-size:10.5pt;font-family:Consolas;color:#666666"><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.55pt"><span style="font-size:10.0pt;font-family:Consolas;color:#666666;background:#FAF6E1">JavaScriptCore JSArray::sort(...) method. This method accepts the user-defined
</span><span style="font-size:10.5pt;font-family:Consolas;color:#666666"><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.55pt"><span style="font-size:10.0pt;font-family:Consolas;color:#666666;background:#FAF6E1">JavaScript function and calls it from the native code to compare array items.
</span><span style="font-size:10.5pt;font-family:Consolas;color:#666666"><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.55pt"><span style="font-size:10.0pt;font-family:Consolas;color:#666666;background:#FAF6E1">If this compare function reduces array length, then the trailing array items
</span><span style="font-size:10.5pt;font-family:Consolas;color:#666666"><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.55pt"><span style="font-size:10.0pt;font-family:Consolas;color:#666666;background:#FAF6E1">will be written outside the "m_storage->m_vector[]" buffer, which leads to the
</span><span style="font-size:10.5pt;font-family:Consolas;color:#666666"><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.55pt"><span style="font-size:10.0pt;font-family:Consolas;color:#666666;background:#FAF6E1">heap memory corruption.</span><span style="font-size:10.5pt;font-family:Consolas;color:#666666"><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.55pt"><span style="font-size:10.5pt;font-family:Consolas;color:#666666"> <o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.55pt"><span style="font-size:10.0pt;font-family:Consolas;color:#666666;background:#FAF6E1">The exploit for this vulnerability is a JavaScript code which shows how to
</span><span style="font-size:10.5pt;font-family:Consolas;color:#666666"><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.55pt"><span style="font-size:10.0pt;font-family:Consolas;color:#666666;background:#FAF6E1">use it for memory corruption of internal JS objects (Unit32Array and etc.)
</span><span style="font-size:10.5pt;font-family:Consolas;color:#666666"><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.55pt"><span style="font-size:10.0pt;font-family:Consolas;color:#666666;background:#FAF6E1">and subsequent arbitrary code execution (custom ARM/x64 payloads can be pasted
</span><span style="font-size:10.5pt;font-family:Consolas;color:#666666"><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.55pt"><span style="font-size:10.0pt;font-family:Consolas;color:#666666;background:#FAF6E1">into the JS code).</span><span style="font-size:10.5pt;font-family:Consolas;color:#666666"><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.55pt"><span style="font-size:10.5pt;font-family:Consolas;color:#666666"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#203864;mso-style-textfill-fill-color:#203864;mso-style-textfill-fill-alpha:100.0%">So our question is, can point us to the fix (i.e. changelist/revision) which patched this exploit?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#203864;mso-style-textfill-fill-color:#203864;mso-style-textfill-fill-alpha:100.0%"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#203864;mso-style-textfill-fill-color:#203864;mso-style-textfill-fill-alpha:100.0%">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#203864;mso-style-textfill-fill-color:#203864;mso-style-textfill-fill-alpha:100.0%">Rupali<o:p></o:p></span></p>
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