ALS_BURSTED.TYM

October 09, 2012
 Analysis by: Joseph Obed
 ALIASES:

Virus:ALisp/Bursted.J(Microsoft), ALS/Bursted(McAfee), ALS.Bursted.B(Symantec), Virus.Acad.Bursted.a(Kaspersky)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan 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:

17,091 bytes

File Type:

LSP

Initial Samples Received Date:

17 Oct 2011

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

NOTES:

This malware arrives in the system as an AutoLISP script bundled with a .DWG drawing file. Once the drawing file is opened, AutoCAD then loads and executes this malware.

It searches for the file BASE.DCL in the AutoCAD search path. It then searches for the file ACAD.LSP from where the file BASE.DCL is located. It then reads the file ACAD.LSP to check the string textdit. If the string is not found, it adds the line (load textdit) to ACAD.LSP.

It overwrites the contents of the file TEXTDIT.LSP with the contents of the modified ACAD.LSP and checks if the name of the drawing file is DRAWING.DWG. If not, it overwrites the contents of the file ACAD.LSP with the contents of TEXTDIT.LSP. This malware disables some editing functionalities of AutoCAD.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.504.02

FIRST VSAPI PATTERN DATE:

17 Oct 2011

VSAPI OPR PATTERN File:

8.505.00

VSAPI OPR PATTERN Date:

18 Oct 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

Scan your computer with your Trend Micro product to delete files detected as ALS_BURSTED.TYM. 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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