VBS_AUTORUN.FKL

October 09, 2012
 Analysis by: Michael Cabel
 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

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.

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:

3,640 bytes

File Type:

VBS

Memory Resident:

Yes

Initial Samples Received Date:

10 Sep 2011

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.

Autostart Technique

This worm drops the following file(s) in the Windows Common Startup folder to enable its automatic execution at every system startup:

  • RegDelete.vbs

Propagation

This worm drops the following copy of itself in all physical and removable drives:

  • RegDelete.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 RegDelete.vbs

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.418.02

FIRST VSAPI PATTERN DATE:

10 Sep 2011

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

Search and delete this file

[ 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.
  • RegDelete.vbs

Step 4

Search and delete AUTORUN.INF files created by VBS_AUTORUN.FKL that contain these strings

[ Learn More ]
[autorun]
shellexecute=wscript.exe RegDelete.vbs

Step 5

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