Analysis by: RonJay Kristoffer Caragay
ALIASES:

Mal/ExpJS-BS (Sophos); Trojan.Malscript (Symantec);

 PLATFORM:

Windows

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

  • 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. It may be hosted on a website and run when a user accesses the said website.

This is the Trend Micro detection for files that contain a malicious script.

  TECHNICAL DETAILS

File Size: 76,853 bytes
File Type: HTML, HTM
Initial Samples Received Date: 30 Sep 2014

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 hosted on a website and run when a user accesses the said website.

Other Details

This is the Trend Micro detection for files that contain a malicious script.

NOTES:
This Trojan may decrypt and execute codes or scripts which depends on the parameter passed on to it by its components.

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 11.182.04
FIRST VSAPI PATTERN DATE: 30 Sep 2014
VSAPI OPR PATTERN File: 11.183.00
VSAPI OPR PATTERN Date: 30 Sep 2014

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Close all opened browser windows

Step 3

Scan your computer with your Trend Micro product to delete files detected as HTML_MALJS.LDBY. 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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