JS_NEMUCOD.ELDSAUJN

August 26, 2017
 Analysis by: Nikko Tamana
 ALIASES:

TrojanDownloader:JS/Nemucod (Microsoft)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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:

12788 bytes

File Type:

JS

Memory Resident:

No

Initial Samples Received Date:

16 Aug 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.

Download Routine

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

  • http://cry{BLOCKED}.ru/versionmaster/nova/load.exe
  • http://mari{BLOCKED}shop.ru/ico/load.exe

It saves the files it downloads using the following names:

  • %User Temp%\{random number from 1 to 1000}.exe - detected as TSPY_ZBOT.XNI

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

NOTES:
It will not execute the downloaded file if system time is later than: 2017-29-08 20:19:34

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.612.04

FIRST VSAPI PATTERN DATE:

16 Aug 2017

VSAPI OPR PATTERN File:

13.613.00

VSAPI OPR PATTERN Date:

17 Aug 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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Remove malware/grayware files dropped/downloaded by JS_NEMUCOD.ELDSAUJN. (Note: Please skip this step if the threats listed below have already been removed.)

     
    • TSPY_ZBOT.XNI

Step 4

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