TrojanSpy.MSIL.EXMATTER.A

February 04, 2022
 Analysis by: Patrick Noel Collado
 ALIASES:

MSIL/Spy.Agent.DRB (Nod32)

 PLATFORM:

Windows

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

  • Threat Type: Trojan Spy

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

This Trojan Spy 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:

1,355,264 bytes

File Type:

EXE

Memory Resident:

Yes

Payload:

Connects to URLs/IPs, Uploads files

Arrival Details

This Trojan Spy 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 Spy adds the following processes:

  • "powershell.exe" -WindowStyle Hidden -C $path = '{Malware Path}\{Malware Name}.exe';Get-Process | Where-Object {$_.Path -like $path} | Stop-Process -Force;[byte[]]$arr = new-object byte[] 455443087;Set-Content -Path $path -Value $arr;Remove-Item -Path $path;

Information Theft

This Trojan Spy accepts the following parameters:

  • nownd or -nownd → executes itself with its window hidden.
  • exists or -exists → checks if file exists

Other Details

This Trojan Spy does the following:

  • Creates a directory at the following URLs where it uploads the files:
    • https://{BLOCKED}.{BLOCKED}.232.192/data/{Machines's Domain Name}.{Machine's Host Name}
    • if there is no Domain Name:
      • https://{BLOCKED}.{BLOCKED}.232.192/data/WORKGROUP.{Machine's Host Name}
  • It takes ownership of its executable folder and removes all other account’s access
  • The files it sends must be from 1 year ago up to 6 years ago from its execution date
  • The files it sends must be from 6 months ago up to 10 years from its execution date
  • It does not send system files, temporary files, and directories
  • It does not send files smaller than 1024 bytes
  • It does not send files with the following file mask:
    • OneDriveMedTile
    • locale-
    • SmallLogo
    • VisualElements
    • adobe_sign
    • Adobe Sign
    • core_icons
  • It does not send files from the following directories:
    • C:\Documents and Settings
    • C:\PerfLogs
    • C:\Program Files\Windows Defender Advanced Threat Protection
    • C:\Program Files\WindowsApps
    • C:\ProgramData\Application Data
    • C:\ProgramData\Desktop
    • C:\ProgramData\Documents
    • C:\ProgramData\Microsoft
    • C:\ProgramData\Packages
    • C:\ProgramData\Start Menu
    • C:\ProgramData\Templates
    • C:\ProgramData\WindowsHolographicDevices
    • C:\Recovery
    • C:\System Volume Information
    • C:\Users\All Users
    • C:\Users\Default
    • C:\Users\Public\Documents
    • C:\Windows
    • System Volume Information
  • It uploads files with the following extensions:
    • .doc
    • .docx
    • .xls
    • .xlsx
    • .xlsm
    • .pdf
    • .msg
    • .ppt
    • .pptx
    • .sda
    • .sdm
    • .sdw
    • .csv
    • .zip
    • .json
    • .config
    • .ts
    • .cs
    • .sqlite
    • .aspx
    • .pst
    • .rdp
    • .accdb
    • .catpart
    • .catproduct
    • .catdrawing
    • .3ds
    • .dwt
    • .dxf

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

17.360.08

FIRST VSAPI PATTERN DATE:

04 Feb 2022

VSAPI OPR PATTERN File:

17.361.00

VSAPI OPR PATTERN Date:

05 Feb 2022

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:

     Ransom.Win32.TRX.XXPE50FFF053

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

Identify and terminate files detected as TrojanSpy.MSIL.EXMATTER.A

[ 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 5

Scan your computer with your Trend Micro product to delete files detected as TrojanSpy.MSIL.EXMATTER.A. 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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