RANSOM_LERITH.J

 Analysis by: Patrick Angelo Roderno

 ALIASES:

Trojan-Ransom.Win32.Cryptor.bfm (KASPERSKY); Ransom:Win32/Genasom (MICROSOFT); Trojan.Gen (NORTON)

 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 encrypts files found in specific folders.

  TECHNICAL DETAILS

File Size:

3,287,040 bytes

File Compression:

UPX

Memory Resident:

No

Initial Samples Received Date:

26 Nov 2017

Payload:

Displays graphics/image, 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:

  • icacls . /grant Everyone:F /T /C /Q
  • vssadmin delete shadow /all /quiet
  • wmic shadowcopy delete
  • bcdedit /set {default} boostatuspolicy ignoreallfailures
  • bcdedit /set {default} recoveryenabled no
  • wbadmin delete catalog -quiet

Autostart Technique

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

HKEY_LOCAL_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Adolf Hitler = “{Full Path of Malware}\{Malware Name}.exe”

Other System Modifications

This Ransomware modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = "0"

(Note: The default value data of the said registry entry is "1".)

It changes the desktop wallpaper by modifying the following registry entries:

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = "%Windows%\{Chineses characters}.bmp"

It sets the system's desktop wallpaper to the following image:

Dropping Routine

This Ransomware drops the following files:

  • %User Temp%\_Adolf Hitler_.mp3 -> played after the execution of the malware
  • %Windows%\{Chinese characters}.bmp
  • %Desktop%\_Adolf Hitler_.bmp
  • {Root directory of infected drives}\_Adolf Hitler_.bmp

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in 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.)

Other Details

This Ransomware displays the following message boxes:


It does the following:

  • Plays an audio file (%User Temp%\_Adolf Hitler_.mp3) during and after the execution of the malware

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)

Ransomware Routine

This Ransomware encrypts files found in the following folders:

  • {All Drives}

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

  • .{random 16-character string}.AdolfHitler

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.810.03

FIRST VSAPI PATTERN DATE:

26 Nov 2017

VSAPI OPR PATTERN File:

13.811.00

VSAPI OPR PATTERN Date:

27 Nov 2017

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

Identify and terminate files detected as RANSOM_LERITH.J

[ 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 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\Microsoft\Windows\CurrentVersion\Run
    • Adolf Hitler = "{Full Path of the Malware}\{Malware Name}.exe}"

Step 5

Restore this modified 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\Microsoft\Windows\CurrentVersion\Policies\System
    • From: EnableLUA = "0"
      To: EnableLUA = "1"

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.  
  • %Windows%\{Chinese characters}.bmp
  • %User Temp%\_Adolf Hitler_.mp3
  • {Root directory of infected drives}\_Adolf Hitler_.bmp
  • %Desktop%\_Adolf Hitler_.bmp

Step 7

Scan your computer with your Trend Micro product to delete files detected as RANSOM_LERITH.J. 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

Reset your Desktop properties

[ Learn More ]

NOTES:

Clean solution:

  1. Enable services disabled through the command prompt.
  2. Run cmd.exe as administrator.
  3. To enable Volume Shadow Service, use the following command:

    net start vss

  4. To enable Windows Error Recovery Screen on Startup, use the command:

    bcdedit /set {default} bootstatuspolicy displayallfailures

  5. To enable Startup Repair, use the command:

    bcedit /set {default} recoveryenabled Yes


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