RANSOM_BLACKMIST.A

June 09, 2018
 Analysis by: John Donnie Celestre
 ALIASES:

Trojan.GenericKD.6035944 (BITDEFENDER); HEUR:Trojan.MSIL.Generic (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 contains errors in its code. This stops it from performing its routines. It deletes itself after execution.

It encrypts files found in specific folders.

  TECHNICAL DETAILS

File Size:

1,709,056 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

28 Sep 2017

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 and executes the following files:

  • %User Temp%\modual.exe <- component file for persistence

(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.)

Autostart Technique

This Ransomware modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\Current Version\Windows
Load = %User Temp%\modual.exe

Process Termination

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

  • explorer
  • taskmgr
  • chrome

Other Details

This Ransomware contains errors in its code. This stops it from performing its routines.

It deletes itself after execution.

Ransomware Routine

This Ransomware encrypts files found in the following folders:

  • C:\Users\Owner\Documents\

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

  • blackmist

NOTES:

This ransomware displays the following:

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.686.04

FIRST VSAPI PATTERN DATE:

28 Sep 2017

VSAPI OPR PATTERN File:

13.687.00

VSAPI OPR PATTERN Date:

29 Sep 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

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 NT\Current Version\Windows
    • Load = %User Temp%\modual.exe

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.
  • %User Temp%\modual.exe

Step 6

Scan your computer with your Trend Micro product to delete files detected as RANSOM_BLACKMIST.A. 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 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_BLACKMIST.A. 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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