Analysis by: Joselyn Canuela
ALIASES:

W97M/Downloader (McAfee), TrojanDownloader:O97M/Donoff (Microsoft), W97M.Downloader (Symantec)

 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

This Trojan arrives as attachment to mass-mailed email messages.

  TECHNICAL DETAILS

File Size: 66,048 bytes
File Type: DOC
Memory Resident: No
Initial Samples Received Date: 25 Aug 2017
Payload: Connects to URLs/IPs, Downloads files

Arrival Details

This Trojan arrives as attachment to mass-mailed email messages.

Installation

This Trojan adds the following processes:

  • powershell.exe

Download Routine

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

  • http://{BLOCKED}is.com/hpV/
  • http://{BLOCKED}n.com/vVKbiCUJ/
  • http://{BLOCKED}f.org/CsGXp/
  • http://{BLOCKED}e.com.hk/yaeRXq/
  • http://{BLOCKED}tudio.org/lEYJk/

It saves the files it downloads using the following names:

  • %Temp%\{random numbers}.exe

(Note: %Temp% is the Windows temporary folder, where it usually is C:\Windows\Temp on all Windows operating system versions.)

Trend Micro detects the dowloaded file as:

Other Details

This is the Trend Micro detection for Microsoft Word documents that are compromised through the insertion of a malicious macro.

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.616.03
FIRST VSAPI PATTERN DATE: 25 Aug 2017
VSAPI OPR PATTERN File: 13.617.00
VSAPI OPR PATTERN Date: 26 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 W2KM_POWLOAD.AUSJRN. (Note: Please skip this step if the threats listed below have already been removed.)

Step 4

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