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WORM_SOBER.AH

October 09, 2012
 Analysis by: Kathleen Notario
 ALIASES:

W32.Sober.X@mm (Symantec); Worm:Win32/Sober.S@mm (Microsoft); W32/Sober@MM!M681 (Mcafee); W32/Sober.AH.worm!CME-681 (Panda)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware


This worm 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:

75,996 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

20 Jul 2009

Arrival Details

This worm 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 worm drops the following copies of itself into the affected system and executes them:

  • %Windows%\WinSecurity\csrss.exe
  • %Windows%\WinSecurity\services.exe
  • %Windows%\WinSecurity\smss.exe
  • %Windows%\WinSecurity\socket1.ifo
  • %Windows%\WinSecurity\socket2.ifo
  • %Windows%\WinSecurity\socket3.ifo

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

It drops the following files:

  • %Windows%\WinSecurity\mssock1.dli
  • %System%\bbvmwxxf.hml
  • %System%\filesms.fms
  • %System%\langeinf.lin
  • %System%\nonrunso.ber
  • %System%\rubezahl.rub
  • %System%\runstop.rst

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It creates the following folders:

  • %Windows%\WinSecurity

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
_Windows = "%Windows%\WinSecurity\services.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Windows = "%Windows%\WinSecurity\services.exe"

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

6.292.03

FIRST VSAPI PATTERN DATE:

20 Jul 2009

VSAPI OPR PATTERN File:

6.293.00

VSAPI OPR PATTERN Date:

20 Jul 2009

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

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
    • _Windows = "%Windows%\WinSecurity\services.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • Windows = "%Windows%\WinSecurity\services.exe"

Step 4

Search and delete this folder

[ 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.
  • %Windows%\WinSecurity

Step 5

Search and delete these files

[ Learn More ]
There may be some component files 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.  
  • %System%\bbvmwxxf.hml
  • %System%\filesms.fms
  • %System%\langeinf.lin
  • %System%\nonrunso.ber
  • %System%\rubezahl.rub
  • %System%\runstop.rst

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_SOBER.AH. 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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