JS_NEMUCOD.ELDSAUCA

February 17, 2017
 Analysis by: Cris Nowell Pantanilla
 ALIASES:

JS.Downloader (Symantec), JS/TrojanDownloader.Nemucod.CFV (NOD32)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • 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:

90,578 bytes

File Type:

, JS

Memory Resident:

No

Initial Samples Received Date:

16 Feb 2017

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.

Installation

This Trojan drops the following copies of itself into the affected system and executes them:

  • %User Startup%\offc_updr.jse

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • https://{BLOCKED}.{BLOCKED}.104.178:4444/C/deerstalker.php

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.224.02

FIRST VSAPI PATTERN DATE:

16 Feb 2017

VSAPI OPR PATTERN File:

13.225.00

VSAPI OPR PATTERN Date:

17 Feb 2017

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

Scan your computer with your Trend Micro product to delete files detected as JS_NEMUCOD.ELDSAUCA. 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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