What Is Vundo Related vtsts.dll?

Windows Security Tutorials - Herong's Tutorial Examples

∟Vundo (VirtuMonde/VirtuMundo) - vtsts.dll Removal

∟What Is Vundo Related vtsts.dll?

This section provides a tutorial example of how to find the root file of trojan Vundo, vtsts.dll.

Of course, this time I had to do more than removing these DLL files. I had to try to find the root of this Trojan Vundo.

So I looked at the HijackThis report carefully again, examining each entry in the report and did Google search on each associated program. When I reached the following entry, I got some interested matches on Google search result:

O2 - BHO: ATLDistrib Object - {93C6313C-9DB4-4694-8BD0-E378C573A9AD}
   - C:\WINDOWS\system32\vtsts.dll

Google Search Result - Part I: When I searched for "vtsts.dll" with Google, I got the following interesting items out of 785 matches:

1. From www.bullguard.com/forum/8/DowloadTrojan-Virus-vtstsdll_14346.html, it's a long forum post and replies dated on May 7, 2005. The infected system has 2 related entries in its HijackThis report:

O2 - BHO: (no name) - {8E13DDE1-E013-47ec-9C4C-27C2F78BDD26}
   - C:\WINDOWS\system32\vtsts.dll
O20 - Winlogon Notify: vtsts - C:\WINDOWS\SYSTEM32\vtsts.dll

Based on the replies, the infected system was cleaned by AVG Antivirus from www.grisoft.com, after several failed attempts from different anti-virus tools.

2. From forums.techguy.org/security/415370-solved-help-remove-downloader-trojan.html, it's a long forum post and replies date on Nov. 9, 2005. The infected system has 3 related entries in its HijackThis report:

O2 - BHO: (no name) - {00DBDAC8-4691-4797-8E6A-7C6AB89BC441}
   - C:\WINDOWS\system32\vtsts.dll
O20 - Winlogon Notify: vtsqr - C:\WINDOWS\system32\vtsqr.dll
O20 - Winlogon Notify: vtsts - C:\WINDOWS\SYSTEM32\vtsts.dll

Based on the replies, the infected system was cleaned by using VundoFix.exe from atribune.org and Killbox from subratam.org, combined with detailed guiding instructions providing by the forum moderator, Flrman1.

This tells me that vtsts.dll is related to Trojan Vundo.

3. From www.lavasoftsupport.com/lofiversion/index.php/t1570.html, it's a long forum post and replies date on Jul. 5, 2006. The infected system has 4 related entries in its HijackThis report:

O2 - BHO: (no name) - {20D57A66-F7DF-467d-907B-9B7F4A118AB7} 
   - C:\WINDOWS\system32\mllmm.dll
O2 - BHO: DosSpecFolder Object {3496D13A-609A-407B-B181-8F47B4F28AE9}
   - C:\WINDOWS\system32\vtsts.dll
O20 - Winlogon Notify: mllmm - C:\WINDOWS\SYSTEM32\mllmm.dll
O20 - Winlogon Notify: vtsts - C:\WINDOWS\system32\vtsts.dll

Removal instuctions were given to use Qoofix from malwarebytes.org and VundoFix.exe from atribune.org. But no final reply on the results of the suggested removal process on the infected system.

Google Search Result - Part II: When I searched for "ATLDistrib Object" with Google, I got the following interesting items out of 9,940 matches:

1. From wiki.castlecops.com/Malware_Removal:_Virtumundo, it's an article about Adware-Virtumundo (Vundo) removal. There are two sets of HijackThis report entries related ATLDistrib Object:

Example 1:
O2 - BHO: ATLDistrib Object - {7A1A109F-58B3-414B-9829-5F4D9BE5FEDE}
   - C:\WINDOWS\system32\mljjj.dll
O20 - Winlogon Notify: mljjj - C:\WINDOWS\system32\mljjj.dll

Example 2:
O2 - BHO: ATLDistrib Object - {7A1A109F-58B3-414B-9829-5F4D9BE5FEDE}
   - C:\WINDOWS\system32\pmnlj.dll
020 - Winlogon Notify: pmnlj - C:\WINDOWS\system32\pmnlj.dll

This confirms that vtsts.dll is related to Trojan Vundo.

2. From www.geekstogo.com/forum/index.php?showtopic=86351, it's a forum post and replies dated on Dec. 23, 2005. The infected system has 2 related entries in its HijackThis report:

O2 - BHO: ATLDistrib Object - {3FE36807-69ED-45D1-B9BE-85C0E3F75B6A}
   - C:\WINDOWS\System32\ddccd.dll
O20 - Winlogon Notify: ddccd - C:\WINDOWS\System32\ddccd.dll

Based on the replies, the infected system was cleaned by using VundoFix.exe, WebRoot SpySweeper, VirtumundoBegone, Panda Active Scan, and Killbox, combined with detailed guiding instructions providing by the Malware Removal Specialist, loophole.

This confirms again that vtsts.dll is related to Trojan Vundo.

Conclusion: vtsts.dll and "ATLDistrib Object" are related to Trojan Vundo. I must missed the vtsts.dll entry from the HijackThis report during my last visit.

From my Google results, all reported cases are having the suspicious DLL file registered as a Winlogon Notify entry. But I could not find any similar "020" entry in my friend's HijackThis report. So this could be new variant of Trojan Vundo.

Or this is a partial broken Trojan Vundo. This seemed to match the symptom that the Internet Explorer pops up, but not showing any target Web sites, and closes up by itself.