Analysis by: Cris Nowell Pantanilla

ALIASES:

TrojanDownloader:JS/Swabfex.S (Microsoft), JS.Downloader (Symantec)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

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 executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size: 4,068 bytes
File Type: JS
Memory Resident: No
Initial Samples Received Date: 18 Feb 2016
Payload: Downloads files, Executes files

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.

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

  • http://{blocked}-kreativ.com/98876hg5/45gt454h
  • http://{blocked}.{blocked}.240.71/~l.pennings/98876hg5/45gt454h

It saves the files it downloads using the following names:

  • %USER TEMP%\{random}.scr

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.350.08
FIRST VSAPI PATTERN DATE: 18 Feb 2016
VSAPI OPR PATTERN File: 12.351.00
VSAPI OPR PATTERN Date: 19 Feb 2016

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

Search and delete these files

[ Learn More ]
There may be some 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.  %USER TEMP%\{random}.scr

Step 3

Scan your computer with your Trend Micro product to delete files detected as JS_DRIDEX.SM. 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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