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PE_VIRUT.NS-3

October 20, 2013
 ALIASES:

Virus:Win32/Virut.D (Microsoft); W32/Virut.gen (McAfee); W32.Virut.H (Symantec); Trojan.Win32.Scar.eaml (Kaspersky); Virus.Win32.Virut.b (v) (Sunbelt); Win32.Virtob.Gen.9 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 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.

  TECHNICAL DETAILS

File Size:

18,432 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

08 Oct 2011

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.

Other System Modifications

This file infector adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
KB475837.exe = ""%User Profile%\Application Data\KB475837.exe""

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
KB475837.exe = ""%User Profile%\Application Data\KB475837.exe""

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Session Manager\SFC
ProgramFilesDir = "%Program Files%"

(Note: The default value data of the said registry entry is %Program Files%.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Session Manager\SFC
CommonFilesDir = "%Program Files%\Common Files"

(Note: The default value data of the said registry entry is %Program Files%\Common Files.)

Dropping Routine

This file infector drops the following files:

  • %User Profile%\Application Data\KB475837.exe
  • %User Temp%\svchost.exe

(Note: %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.. %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.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • KB475837.exe=""%User Profile%\Application Data\KB475837.exe""
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • KB475837.exe=""%User Profile%\Application Data\KB475837.exe""

Step 3

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Session Manager\SFC
    • From: ProgramFilesDir="%Program Files%"
      To: ProgramFilesDir=%Program Files%
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Session Manager\SFC
    • From: CommonFilesDir="%Program Files%\Common Files"
      To: CommonFilesDir=%Program Files%\Common Files

Step 4

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 Profile%\Application Data\KB475837.exe
  • %User Temp%\svchost.exe

Step 5

Scan your computer with your Trend Micro product to clean files detected as PE_VIRUT.NS-3. 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.


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