Ransom.Win64.BABUK.YXDDYZ

May 25, 2023
 Analysis by: Jayvee Mark Villaroman
 ALIASES:

Ransom:Win32/Aicat.A!ml (MICROSOFT), Ransom.Babuk (MALWAREBYTES)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: No

  • 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.

  TECHNICAL DETAILS

File Size:

57,344 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

17 May 2023

Payload:

Deletes files, Encrypts files

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 adds the following mutexes to ensure that only one of its copies runs at any one time:

  • DoYouWantToHaveSexWithCuongDong

Other Details

This Ransomware does the following:

  • Empties the recycle bin upon execution.
  • Deletes shadow copies using vssadmin.exe
    • /c vssadmin.exe delete shadows /all /quiet
  • Encrypts data found in drives A-Z, except CD-ROM.
  • Encrypts network shares.

Ransomware Routine

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

  • autorun.inf
  • boot.ini
  • bootfont.bin
  • bootmgfw.efi
  • bootmgr
  • bootmgr.efi
  • bootsect.bak
  • desktop.ini
  • iconcache.db
  • ntldr
  • ntuser.dat
  • ntuser.dat.log
  • ntuser.ini
  • thumbs.db

It avoids encrypting files found in the following folders:

  • $Recycle.Bin
  • All Users
  • AppData
  • Boot
  • Google
  • Internet Explorer
  • Mozilla
  • Mozilla Firefox
  • Opera
  • Opera Software
  • Program Files
  • Program Files (x86)
  • ProgramData
  • Tor Browser
  • Windows
  • Windows.old

It appends the following extension to the file name of the encrypted files:

  • {Encrypted File}.{Original Extension}.GAGUP

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

  • How To Restore Your Files.txt

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

18.405.00

FIRST VSAPI PATTERN DATE:

25 Apr 2023

VSAPI OPR PATTERN File:

18.405.00

VSAPI OPR PATTERN Date:

25 Apr 2023

Step 1

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 2

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.
  • {All Affected Drives}\How To Restore Your Files.txt 

Step 3

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win64.BABUK.YXDDYZ. 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 4

Restore encrypted files from backup.


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