ALIASES:

Virus:Win32/Virut.BH (Microsoft); [2.nsis]:W32/Virut.j, [3.nsis\2.nsis]:Downloader.a!cm3, [4.nsis\2.nsis]:Downloader.a!cm3, [5.nsis]:D (McAfee); Trojan Horse (Symantec); Virus.Win32.Virut.bn (Kaspersky); Virus.Win32.Virut.a (v), Trojan.Win32.Generic!BT, Trojan.Win32.Generic!BT, Trojan.Win32.Tibs.ho (v) (Sunbelt); Win32.Virut.M (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • Threat Type: File infector

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This file infector arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It disables Task Manager, Registry Editor, and Folder Options.

  TECHNICAL DETAILS

File Size: 92,175 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 04 Dec 2012

Arrival Details

This file infector arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This file infector creates the following folders:

  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\Wilbert
  • %User Profile%\LOCALS~1

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

Autostart Technique

This file infector adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
System32 = "%System%\update32.exe"

Other System Modifications

This file infector deletes the following files:

  • %User Temp%\nsb1.tmp
  • %User Temp%\nsi3.tmp
  • %User Temp%\nsu5.tmp
  • %System%\update32.exe
  • %System%\dlds8.exe
  • %User Temp%\1.df1lb
  • %User Temp%\2.df1lb
  • %User Temp%\5.df1lb
  • %User Temp%\6.df1lb
  • %User Temp%\7.df1lb

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System

It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "1"

Dropping Routine

This file infector drops the following files:

  • %User Temp%\nsq2.tmp
  • %User Temp%\load20.exe
  • %User Temp%\stat1.exe
  • %User Temp%\forads.exe
  • %User Temp%\newwin32.exe
  • %User Temp%\nsy4.tmp
  • %User Temp%\Oct2008.exe
  • %User Temp%\Oct2008.txt
  • %User Temp%\nsz6.tmp
  • %System%\update32.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other Details

This file infector connects to the following possibly malicious URL:

  • http://{BLOCKED}pa.info/cr/ld.php?i=20
  • http://{BLOCKED}t.net/cc/ccdo.php?affid=9
  • http://{BLOCKED}t.net/out/search.jpg
  • http://{BLOCKED}t.net/out/winlogon.jpg
  • http://{BLOCKED}t.net/out/tibs.jpg
  • http://{BLOCKED}t.net/out/tool.jpg
  • http://{BLOCKED}t.net/out/proxy.jpg
  • http://www41.{BLOCKED}ba.com/cashgame/freegame.files/ad.exe
  • http://{BLOCKED}t.net/cc/srtytrewqertytrew.php?affid=9&code1=HPNI&code2=1365

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.300

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Enable Registry Editor, Task Manager, and Folder options

[ Learn More ]
By doing this step, you also enable other applications/programs disabled by this malware/grayware/spyware.

Step 4

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
    • System

Step 5

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • System32 = "%System%\update32.exe"

Step 6

Search and delete these components

[ Learn More ]
There may be some components that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %User Temp%\nsq2.tmp
  • %User Temp%\load20.exe
  • %User Temp%\stat1.exe
  • %User Temp%\forads.exe
  • %User Temp%\newwin32.exe
  • %User Temp%\nsy4.tmp
  • %User Temp%\Oct2008.exe
  • %User Temp%\Oct2008.txt
  • %User Temp%\nsz6.tmp
  • %System%\update32.exe

Step 7

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\Wilbert
  • %User Profile%\LOCALS~1

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as PE_VIRUT.TUR. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Step 9

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %User Temp%\nsb1.tmp
  • %User Temp%\nsi3.tmp
  • %User Temp%\nsu5.tmp
  • %System%\update32.exe
  • %System%\dlds8.exe
  • %User Temp%\1.df1lb
  • %User Temp%\2.df1lb
  • %User Temp%\5.df1lb
  • %User Temp%\6.df1lb
  • %User Temp%\7.df1lb


Did this description help? Tell us how we did.