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Trojan.VBS.POWLOAD.AB

September 20, 2018
 Analysis by: John Rey Canon
 ALIASES:

Trojan:PowerShell/Encropow (Microsoft); Trojan.PowerShell.Encropow (Ikarus); MSH.Downloader (Norton)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • 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.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

5,996 bytes

File Type:

VBS

Memory Resident:

No

Initial Samples Received Date:

19 Sep 2018

Payload:

Connects to URLs/IPs

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 files:

  • %User Temp%\tmp.ps1
  • %Application Data%\Microsoft\Windows\Recent\CustomDestinations\{Random Text}.temp
  • %Application Data%\Microsoft\Windows\Recent\CustomDestinations\{Random Text}.customDestinations-ms
  • %User Temp%\tmp.jpg

(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, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://png.{BLOCKED}menews.tk/m.png

It does the following:

  • Adds the following scheduled tasks:
    • "Update "
      • Execute every 6 minutes
      • Execute following using powershell:
        • %User Temp%\tmp.ps1

(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, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.)

However, as of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.514.03

FIRST VSAPI PATTERN DATE:

19 Sep 2018

VSAPI OPR PATTERN File:

14.515.00

VSAPI OPR PATTERN Date:

20 Sep 2018

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

Search and delete this file

[ Learn More ]
There may be some files 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 Temp%\tmp.ps1
  • %User Temp%\tmp.jpg
  • %Application Data%\Microsoft\Windows\Recent\CustomDestinations\{Random Text}.temp
  • %Application Data%\Microsoft\Windows\Recent\CustomDestinations\{Random Text}.customDestinations-ms

Step 4

Scan your computer with your Trend Micro product to delete files detected as Trojan.VBS.POWLOAD.AB. 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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