Analysis by: Sabrina Lei Sioting

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This is the Trend Micro detection for a specially crafted AutoCAD LISP script file.

It drops copies of itself in all folders where the AutoCAD drawing file are located to enable its propagation.

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. It may be manually installed by a user.

  TECHNICAL DETAILS

File Size: 3,038 bytes
File Type: LSP
Initial Samples Received Date: 17 Nov 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.

It may be manually installed by a user.

NOTES:

This is the Trend Micro detection for a specially crafted AutoCAD LISP script file. It searches for the file BASE.DCL to determine the directory where AutoCAD is installed. It then searches for ACAD.LSP.

It checks the file ACAD.LSP contains the string acadiso. If not, it writes the following string to the said file: load acadaiso. When an AutoCAD drawing file is opened, this script is also executed.

It drops the following copies of itself in all folders where the AutoCAD drawing file are located:

  • acadio.lsp
  • acad.lsp

The said action enables this malware to propagate through all drives.

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 8.580.06
FIRST VSAPI PATTERN DATE: 17 Nov 2011
VSAPI OPR PATTERN File: 8.581.00
VSAPI OPR PATTERN Date: 17 Nov 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 ACM_BURSTED.VI. 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.

NOTES:

Please refer to the following AutoCAD Support page for additional steps in removing this malware:


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