Analysis by: Kathleen Notario
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This worm drops copies of itself in all removable drives. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size: 96,397 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 04 Oct 2010

Installation

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

  • %User Temp%\{malware filename}.exe
  • %System%\rundll.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.. %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.)

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 Firevall Control Center = %System%\rundll.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Windows Firevall Control Center = %System%\rundll.exe

Propagation

This worm drops copies of itself in all removable drives.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

;{garbage characters}
[Autorun] ;{garbage characters}
iCon={garbage characters}ystemroot\system32\shell32.dll ,4;{garbage characters}
Action=Open folder to view files
sHelLexEcUte={malware filename}.exe -[ls]
;{garbage characters}

  SOLUTION

Minimum Scan Engine: 8.900

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 Firevall Control Center=%System%\rundll.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • Windows Firevall Control Center=%System%\rundll.exe

Step 4

Search and delete AUTORUN.INF files created by WORM_BUZUS.BBU that contain these strings

[ Learn More ]
;{garbage characters}
[Autorun] ;{garbage characters}
iCon={garbage characters}ystemroot\system32\shell32.dll ,4;{garbage characters}
Action=Open folder to view files
sHelLexEcUte={malware filename}.exe -[ls]
;{garbage characters}

Step 5

Scan your computer with your Trend Micro product to delete files detected as WORM_BUZUS.BBU. 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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