Content In Brief

An exploit kit, namely The KaiXin Exploit Kit, was discovered roughly 4 months ago by the malware analyst community. I also posted a decent report of this malware back in August. Since then, KaiXin has made another go for it, introducing Version 1.1, which was blogged today by Eric Romang.

I immediately set out to compare file sizes and detection number on VirusTotal. What I found out was rather shocking. Check out the results of 2 different variants, both shellcode exploits [Note: names are randomly generated, but the size of the files are so similar as to assume they are different variants]:

KaiXin Version 1.0 (cLpl7.html)
[NEW] KaiXin Version 1.1 (JSZlR.html)

KaiXin Version 1.0 (gADSr.html)
[NEW] KaiXin Version 1.1 (WysBRr.html)

The detection rate is lower than before. Why is that?

Keep searching,
~!Donovan