Analysis by: Arianne Grace Dela Cruz
ALIASES:

TrojanDownloader:O97M/Obfuse.KW!MTB (Microsoft); RDN/Generic Downloader.x (McAfee); Troj/DocDl-VSY (Sophos)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • 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: 261,580 bytes
File Type: DOC
Initial Samples Received Date: 20 Sep 2019

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:

  • powershell -encod [Base64 Encoded Command]

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\71.exe
  • %User Temp%\{random}.ps1
  • %User Temp%\{random}.psm1

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

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://cengizguler.{BLOCKED}m.tr/wp-content/RvpHbye
  • http://www.{BLOCKED}guler.com.tr/wp-content/RvpHbye
  • http://www.{BLOCKED}medsshop.com
  • http://{BLOCKED}cipeslchf.site
  • http://{BLOCKED}ngals.info
  • http://bikelovers.{BLOCKED}g.br

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 15.378.04
FIRST VSAPI PATTERN DATE: 20 Sep 2019
VSAPI OPR PATTERN File: 15.379.00
VSAPI OPR PATTERN Date: 21 Sep 2019

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

     Downloader.VBA.TRX.XXVBAF01FF005

Step 2

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 3

Identify and terminate files detected as Trojan.W97M.POWLOAD.THIBOAI

[ 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

Search and delete these components

[ Learn More ]
There may be some components 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 Profile%\71.exe
  • %User Temp%\{random}.ps1
  • %User Temp%\{random}.psm1

Step 5

Scan your computer with your Trend Micro product to delete files detected as Trojan.W97M.POWLOAD.THIBOAI. 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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