Trojan-Downloader:W32/Tibs.VX

Classification

Category :

Malware

Type :

Trojan-Downloader

Aliases :

Trojan-Downloader:W32/Tibs.VX, Trojan-Downloader.Win32.Agent.ajbg, Trojan-Downloader:W32/Tibs.VX, TrojanDownloader:Win32/Tibs (Microsoft)

Summary

This malware downloads files into the system and executes them.

Removal

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

Tibs.VX executes netsh.exe, a Windows command line utility, in order to allow the malware to bypass the Windows Firewall.It sends the following system information to http://pluscount.net:

  • Platform
  • Service Pack and Version

Files Created

  • %windir%\system32\winds32.exe
  • %windir%\system32\dflgh8jkd2q1.exe
  • %windir%\system32\dflgh8jkd2q2.exe
  • %windir%\system32\dflgh8jkd2q5.exe
  • %windir%\system32\dflgh8jkd2q6.exe
  • %windir%\system32\dflgh8jkd2q7.exe
  • %windir%\system32\dflgh8jkd2q8.exe
  • %windir%\system32\vx.tll

The downloaded files are detected as Trojan:W32/Tibs.NO, Trojan:W32/Tibs.NS, Trojan:W32/Tibs.NQ, Trojan:W32/Tibs.NR, Trojan:W32/Tibs.NP.The file called winds32.exe is a copy of original sample. The file called vx.tll is a 1 byte file.Temporary placeholders for the downloaded files:

  • %temp%\1.dflb
  • %temp%\2.dflb
  • %temp%\3.dflb
  • %temp%\4.dflb
  • %temp%\5.dflb
  • %temp%\6.dflb
  • %temp%\7.dflb

Network

Tibs.VX attempts to download files from:

  • http://pluscount.net/[...]/search.jpg
  • http://pluscount.net/[...]/winlogon.jpg
  • http://pluscount.net/[...]/tibs.jpg
  • http://pluscount.net/[...]/null.jpg
  • http://pluscount.net/[...]/tool.jpg
  • http://pluscount.net/[...]/proxy.jpg

These URLs contain valid JPEG files with the malware code appended on them. The malware code is hidden via an XOR operation.

File System Changes

Creates these files:

  • %temp%\1.dflb
  • %temp%\2.dflb
  • %temp%\3.dflb
  • %temp%\4.dflb
  • %temp%\5.dflb
  • %temp%\6.dflb
  • %temp%\7.dflb
  • %windir%\system32\dflgh8jkd2q1.exe
  • %windir%\system32\dflgh8jkd2q2.exe
  • %windir%\system32\dflgh8jkd2q5.exe
  • %windir%\system32\dflgh8jkd2q6.exe
  • %windir%\system32\dflgh8jkd2q7.exe
  • %windir%\system32\dflgh8jkd2q8.exe
  • %windir%\system32\vx.tll
  • %windir%\system32\winds32.exe

Network Connections

Attempts to download files from:

  • Http://pluscount.net/[...]/search.jpg
  • http://pluscount.net/[...]/winlogon.jpg
  • http://pluscount.net/[...]/tibs.jpg
  • http://pluscount.net/[...]/null.jpg
  • http://pluscount.net/[...]/tool.jpg
  • http://pluscount.net/[...]/proxy.jpg

Registry Modifications

Sets these values:

  • HKLM\Software\Microsoft\Windows\CurrentVersion\Run System32 = C:\WINDOWS\system32\winds32.exe
  • HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System DisableTaskMgr = 00000001