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Showing posts from February, 2013

Deobfuscating Java 7u11 Exploit from Cool Exploit Kit (CVE-2013-0431)

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At the beginning of the past week @EKWatcher  has spotted Cool Exploit Kit using Java 7 update 11 vulnerability (CVE-2013-0431). This vulnerability was already reported by Security Explorations on seclist few days after Oracle issued update 11. I decided take a look at it. I found a website infected by Cool EK that after a successfull exploitation dropped Reveton into " C:\Documents and Settings\<usarname>\Application Data " folder on Windows XP. The applet used by Cool EK was named would-blood.jar and once opened with JD-GUI the result was this. As you can see it's obfuscated, not heavily but obfuscated. The first thing to do when you want to start deobfuscating an applet is to find the init() function which is the "starting point" and cannot be changed. Remember that for serialized applets the starting point is a function called start() instead of init(). The init function is inside  hw class. It's immediately evident that al