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RANSOM_BTCWARE.THABIH

February 08, 2018
 Analysis by: Camille Reyes
 ALIASES:

Ransom.BTCware (NORTON); Trojan-Ransom.Win32.Foreign.nxtl (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 is capable of encrypting files in the affected system.

It encrypts files found in specific folders. It drops files as ransom note.

  TECHNICAL DETAILS

File Size:

929,792 bytes

File Type:

, EXE

Memory Resident:

No

Initial Samples Received Date:

23 Jan 2018

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 drops the following copies of itself into the affected system:

  • %Application Data%\info.exe

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

Autostart Technique

This Ransomware adds the following registry entries to enable its automatic execution at every system startup:

HKCU\Software\Microsoft\
Windows\CurrentVersion\Run
Encrypter = %Application Data%\info.exe

Other System Modifications

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

HKCU\Software\Microsoft\
Windows\CurrentVersion\Run
userinfo = %Application Data%\recovery.txt

HKCU\Software\Encrypt Keys
local_enc_private_key_len = {hex values}

HKCU\Software\Encrypt Keys
local_enc_private_key = {hex values}

HKCU\Software\Encrypt Keys
local_enc_public_key_len = {hex values}

HKCU\Software\Encrypt Keys
local_enc_public_key = {hex values}

Other Details

This Ransomware is capable of encrypting files in the affected system.

It executes the following command to disable/stop/delete Windows components:

  • cmd.exe /c vssadmin.exe Delete Shadows /All /Quiet
  • cmd.exe /c bcdedit.exe /set {default} recoveryenabled No
  • cmd.exe /c bcdedit.exe /set {default} bootstatuspolicy ignoreallfailures
  • cmd.exe /c taskkill /f /im oracle.exe
  • cmd.exe /c taskkill /f /im sqlite.exe
  • cmd.exe /c taskkill /f /im sql.exe

Ransomware Routine

This Ransomware encrypts files found in the following folders:

  • {Drive Letter}:\

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

  • Windows
  • temp
  • intel
  • nvidia
  • ProgramData

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

  • rapid

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

  • %Application Data%\recovery.txt - inside the folder of the malware copy
  • How Recovery Files.txt - inside the folder/s where files are encrypted

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

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

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.934.01

FIRST VSAPI PATTERN DATE:

28 Jan 2018

VSAPI OPR PATTERN File:

13.935.00

VSAPI OPR PATTERN Date:

29 Jan 2018

Step 1

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

Step 2

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 3

Restart in Safe Mode

[ Learn More ]

Step 4

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\Microsoft\Windows\CurrentVersion\Run
    • Encrypter = %Application Data%\info.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • userinfo = %Application Data%\recovery.txt
  • In HKEY_CURRENT_USER\Software\Encrypt Keys
    • local_enc_private_key_len = {hex values}
  • In HKEY_CURRENT_USER\Software\Encrypt Keys
    • local_enc_private_key = {hex values}
  • In HKEY_CURRENT_USER\Software\Encrypt Keys
    • local_enc_public_key_len = {hex values}
  • In HKEY_CURRENT_USER\Software\Encrypt Keys
    • local_enc_public_key = {hex values}

Step 5

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.
  • %Application Data%\info.exe
  • %Application Data%\recovery.txt
  • How Recovery Files.txt

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_BTCWARE.THABIH. 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 7

Scan your computer with your Trend Micro product to delete files detected as RANSOM_BTCWARE.THABIH. 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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