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Ransom.Win32.BURAN.THHOHAIA

August 28, 2019
 Modified by: Jemimah Mae Molina
 ALIASES:

Ransomware-GPQ!EF4E4CD02B95 (McAfee); HEUR:Trojan-Ransom.Win32.Gen.gen (Kaspersky)

 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:

Dropped by other malware, Downloaded from the Internet


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:

180,224 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

07 Aug 2019

Payload:

Displays message/message boxes, 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 processes:

  • chcp 1250 → changes console page to 1250
  • net view → shows a list of computers and network devices on the network
  • notepad.exe %Desktop%\!!! YOUR FILES ARE ENCRYPTED !!!.TXT

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

Other System Modifications

This Ransomware adds the following registry keys:

HKEY_CURRENT_USER\Software\Buran III\
Service

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Buran III\
Service
Public Key = "{random characters}"

HKEY_CURRENT_USER\Software\Buran III\
Service
Machine ID = "{random characters}"

Other Details

This Ransomware does the following:

  • It terminates itself if the language of the target machine is any of the following:
    • Ukrainian
    • Belarusian
    • Russian
    • Kazak

Ransomware Routine

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

  • boot.ini
  • bootfont.bin
  • bootsect.bak
  • desktop.ini
  • ctfmon.exe
  • iconcache.db
  • master.exe
  • master.dat
  • ntdetect.com
  • ntldr
  • ntuser.dat
  • ntuser.dat.log
  • ntuser.ini
  • thumbs.db
  • !!! your files are encrypted !!!.txt
  • .bat
  • .cmd
  • .com
  • .cpl
  • .dll
  • .msc
  • .msp
  • .pif
  • .scr
  • .sys
  • .log
  • .exe
  • .lnk
  • .buran

It avoids encrypting files found in the following folders:

  • :\$RECYCLE.BIN\
  • :\$Windows.~bt\
  • :\RECYCLER
  • :\System Volume Information\
  • :\Windows.old\
  • :\Windows\
  • :\intel\
  • :\nvidia\
  • :\inetpub\logs\
  • \All Users\
  • \AppData\
  • \Apple Computer\Safari\
  • \ApplicationData\
  • \Boot\
  • \Google\
  • \Google\Chrome\
  • \Mozilla Firefox\
  • \Mozilla\
  • \Opera Software\
  • \Opera\
  • \Tor Browser\
  • \Common Files\
  • \Internet Explorer\
  • \Windows Defender\
  • \Windows Mail\
  • \Windows Media Player\
  • \Windows Multimedia Platform\
  • \Windows NT\
  • \Windows Photo Viewer\
  • \Windows Portable Devices\
  • \WindowsPowerShell\
  • \Windows Photo Viewer\
  • \Windows Security\
  • \Embedded Lockdown Manager\
  • \Windows Journal\
  • \MSBuild\
  • \Reference Assemblies\
  • \Windows Sidebar\
  • \Windows Defender Advanced Threat Protection\
  • \Microsoft\
  • \Package Cache\
  • \Microsoft Help\
  • \Desktop\

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

  • .{{8 random characters}-{4 random characters}-{4 random characters}-{4 random characters}-{12 random characters}}

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

  • %Desktop%\!!! YOUR FILES ARE ENCRYPTED !!!.TXT
  • {Encrypted Directory}\!!! YOUR FILES ARE ENCRYPTED !!!.TXT

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

It leaves text files that serve as ransom notes containing the following text:

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.286.03

FIRST VSAPI PATTERN DATE:

08 Aug 2019

VSAPI OPR PATTERN File:

15.287.00

VSAPI OPR PATTERN Date:

09 Aug 2019

Step 1

Trend Micro products with the XGen technology detect this malware as

[ Learn More ]
 
  • Troj.Win32.TRX.XXPE50FFF031

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

Identify and terminate files detected as Ransom.Win32.BURAN.THHOHAIA

[ 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 4

Delete this registry key

[ 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_CURRENT_USER\Software\Buran III
    • Service

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_CURRENT_USER\Software\Buran III\Service
    • Public Key = {random characters}
  • In HKEY_CURRENT_USER\Software\Buran III\Service
    • Machine ID = {random characters}

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.
  • %Desktop%\!!! YOUR FILES ARE ENCRYPTED !!!.TXT
  • {Encrypted Directory}\!!! YOUR FILES ARE ENCRYPTED !!!.TXT

Step 7

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.BURAN.THHOHAIA. 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 8

Restore encrypted files from backup.


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