VBS_AUTORUN.VT

October 09, 2012
 Analysis by: Erika Bianca Mendoza
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This worm may be unknowingly downloaded by a user while visiting malicious websites.

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:

4,286 bytes

File Type:

VBS

Memory Resident:

Yes

Initial Samples Received Date:

10 May 2011

Arrival Details

This worm may be unknowingly downloaded by a user while visiting malicious websites.

Installation

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

  • %User Temp%\stop-virus.vbs

(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.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\run
SysDll11 = "wscript.exe %User Temp%\stop-virus.vbs"

Propagation

This worm drops the following copy(ies) of itself in all removable drives:

  • stop-virus.vbs

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:

[autorun]
shellexecute=wscript.exe stop-virus.vbs

  SOLUTION

Minimum Scan Engine:

8.900

NOTES:

Trend customers:

    Keep your pattern and scan engine files updated. Trend Micro antivirus software can clean or remove most types of computer threats. Malware, though, such as Trojans, scripts, overwriting viruses and joke programs which are identified as uncleanable, should simply be deleted.

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  • Use HouseCall - the Trend Micro online threat scanner to check for malware that may already be on your PC.
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