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Trojan and Adware - Vundo (vtsts.dll) Removal
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This chapter describes:
- Removing Suspicious xxxxxxxx.dll Files
- What Is vtsts.dll?
- Where Is vtsts.dll Hiding?
- Trying to Remove Trojan Vundo with FixVundo.exe from Symantec
- Removing Trojan Vundo with VundoFix.exe from Atribune.org
Of course, my friend called me a couple of weeks after I helped him on analyzing his adware infected Windows system.
If you read my last report, you know that I only able to identify that the infection
was a Trojan Vundo. I was able to remove only some DLL files named with 8 random letters. His infection was not fully removed.
So I visited his Windows system again. After spending a couple of hours, I believe I did a full removal of a Trojan Vundo
from his Windows system. Here are my notes that may help you if your Windows system gets a similar infection.
Removing Suspicious xxxxxxxx.dll Files
Symptom: My friend told me that the same behavior was still happening. Once a while, Internet Explorer will start
a new window. That new window will run something for a few seconds causing CPU usage to go near 100%, then close itself.
HiJackThis Findings: Running HiJackThis and comparing the report with the report from my last visit, I saw new
"O2 - BHO" line like this:
O2 - BHO: (no name) - {F18F04B0-9CF1-4b93-B004-77A288BEE28B}
- C:\WINDOWS\system32\gidijvia.dll
File System Checking: Using File Explorer, I saw two suspicious DLL files:
>dir C:\WINDOWS\system32\*.dll
10/29/2006 09:34 PM 60,436 swcskmxu.dll
10/31/2006 09:59 PM 60,436 gidijvia.dll
IE Addon Checking: Looking at IE > Internet Options > Programs > Manage Addon,
I found the gidijvia.dll entry.
Analysis: Trojan Vundo is hiding somewhere on the system. It keeps creating new
DLL files. But these DLL files are having different file sizes, comparing to those I captured
from my last visit:
10/02/2006 10:42 PM 86,068 fcissfvg.dll
10/03/2006 10:31 PM 86,036 lyssmlnb.dll
10/12/2006 09:52 PM 98,324 yjsallam.dll
My guess is that this Trajon Vundo is periodically going back to its base Website
to get updates and produce different versions of DLL files.
(Continued on next part...)
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