Analysis by: Karen Ivy Titiwa
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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 inserts an IFRAME tag that redirects users to certain URLs.

  TECHNICAL DETAILS

File Size: 12,558 bytes
File Type: JS
Memory Resident: Yes
Initial Samples Received Date: 24 Oct 2020

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.

Other Details

This Trojan inserts an IFRAME tag that redirects users to the following URLs:

  • http://{BLOCKED}.bycontext.com/scjs/ctxjs/registry.php?affid={random}&subaff={random}&brand={random}&intrstcial={random}&c={random}&oc={random}
  • http://{BLOCKED}.bycontext.com/scjs/ctxjs/log_ctxjs_popularity.php?cctx={random}&dctx={random}&uctx={random}&pctx={random}
  • http://{BLOCKED}.bycontext.com/scjs/ctxjs/log_contx.php?cctx={random}&chctx={channel_id}&dctx={random}&uctx={random}

It does the following:

  • Attempts to obtain the query values from script elements which contain the string "scjs/cjs/ctxjs.js" in its URI

It requires being hosted on a web server in order to proceed with its intended routine.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.320.05
FIRST VSAPI PATTERN DATE: 31 Oct 2020
VSAPI OPR PATTERN File: 16.321.00
VSAPI OPR PATTERN Date: 01 Nov 2020

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

Scan your computer with your Trend Micro product to delete files detected as Trojan.JS.IFRAME.AM. 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 the following Trend Micro Support pages for more information:


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