Analysis by: Clive Fuentebella
ALIASES:

TScope.Trojan.Delf (VBA32)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This Ransomware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It drops files as ransom note. It avoids encrypting files with the following file extensions.

  TECHNICAL DETAILS

File Size: 2,134,528 bytes
File Type: EXE
Memory Resident: Yes
Payload: Modifies system registry, Terminates processes

Arrival Details

This Ransomware 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 Ransomware drops the following files:

  • %AppDataLocal%\{Random characters}.ico (Icon for encrypted files)

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

It adds the following processes:

  • {Malware file path and name}

Other System Modifications

This Ransomware adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.{Random characters}
(Default) = {Random characters}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
{Random chracters}\DefaultIcon
(Default) = %AppDataLocal%\{Random characters}.ico

Process Termination

This Ransomware terminates the following services if found on the affected system:

  • vss
  • sql
  • svc$
  • memtas
  • mepocs
  • sophos
  • veeam
  • backup
  • GxVss
  • GxBlr
  • GxFWD
  • GxCVD
  • GxCIMgr

It terminates the following processes if found running in the affected system's memory:

  • sql
  • oracle
  • ocssd
  • dbsnmp
  • synctime
  • agntsvc
  • isqlplussvc
  • xfssvccon
  • mydesktopservice
  • ocautoupds
  • encsvc
  • firefox
  • tbirdconfig
  • mydesktopqos
  • ocomm
  • dbeng50
  • sqbcoreservice
  • excel
  • infopath
  • msaccess
  • mspub
  • onenote
  • outlook
  • powerpnt
  • steam
  • thebat
  • thunderbird
  • visio
  • winword
  • wordpad
  • notepad

Other Details

This Ransomware does the following:

  • It empties the recycle bin.
  • It deletes shadow copies.

Ransomware Routine

This Ransomware avoids encrypting files with the following strings in their file path:

  • $recycle bin
  • config.msi
  • $windows.~bt
  • $windows.~ws
  • windows
  • appdata
  • application data
  • boot
  • google
  • mozilla
  • program files
  • program files (x86)
  • programdatasystem
  • volume information
  • tor browser
  • windows.old
  • intel
  • msocache
  • perflogs
  • x64dbg
  • public
  • all users
  • default
  • autorun.inf
  • boot.ini
  • bootfont.bin
  • bootsect.bak
  • desktop.ini
  • iconcache.db
  • ntldr
  • ntuser.dat
  • ntuser.dat.log
  • ntuser.ini
  • thumbs.db

It drops the following file(s) as ransom note:

  • {Encrypted folder}\README.{Random characters}.TXT

It avoids encrypting files with the following file extensions:

  • 386
  • adv
  • ani
  • bat
  • bin
  • cab
  • cmd
  • com
  • cpl
  • cur
  • deskthemepack
  • diagcab
  • diagcfg
  • diagpkg
  • dll
  • drv
  • exe
  • hlp
  • icl
  • icns
  • ico
  • ics
  • idx
  • ldf
  • lnk
  • mod
  • mpa
  • msc
  • msp
  • msstyles
  • msu
  • nls
  • nomedia
  • ocx
  • prf
  • ps1
  • rom
  • rtp
  • scr
  • shs
  • spl
  • sys
  • theme
  • themepack
  • wpx
  • lock
  • key
  • hta
  • msi
  • pdb
  • {Appended extension}

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.572.03
FIRST VSAPI PATTERN DATE: 03 Mar 2021
VSAPI OPR PATTERN File: 16.573.00
VSAPI OPR PATTERN Date: 04 Mar 2021

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:

    • Troj.Win32.TRX.XXPE50FFF042

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

Restart in Safe Mode

[ Learn More ]

Step 5

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.{Random characters}
    • (Default)={Random characters}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\{Random chracters}\DefaultIcon
    • (Default)=%AppDataLocal%\{Random characters}.ico

Step 6

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%\{Random characters}.ico (Icon for encrypted files)
    • {Encrypted folder}\README.{Random characters}.TXT

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.DARKSIDE.FAIN. 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 this Knowledge Base page for more information.

Step 8

Restore encrypted files from backup.


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