Analysis by: Camille Reyes
ALIASES:

Ransom:Win32/Genasom (Microsoft); Ransom.BlackOut (Malwarebytes); Troj/Fantom-C (Sophos AV)

 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 deletes itself after execution.

It drops files as ransom note.

  TECHNICAL DETAILS

File Size: 219,648 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 13 Jul 2017
Payload: Encrypts files, Drops files, Terminates processes, Displays message/message boxes

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 files:

  • %User Temp%\backup\BACKUP_{7 random Numbers}.txt

(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.)

It drops and executes the following files:

  • %Application Data%\delback.bat
  • {Malware Path}\update.bat

(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.)

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = 1

Process Termination

This Ransomware terminates processes or services that contain any of the following strings if found running in the affected system's memory:

  • taskmgr
  • sqlagent
  • sqlbrowser
  • sqlservr
  • sqlwriter
  • oracle

Other Details

This Ransomware does the following:

  • It terminates and deletes itself if the Language Culture Name of the affected machine has the following strings: ru, uk, kk, ky, hy and ka.

It deletes itself after execution.

Ransomware Routine

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

  • .lnk
  • README_

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

  • WINDOWS
  • RECYCLER
  • Program Files
  • Program Files (x86)
  • Windows
  • Recycle.Bin
  • RECYCLE.BIN
  • Recycler
  • TEMP
  • APPDATA
  • AppData
  • Temp
  • ProgramData
  • Microsoft
  • Burn

It renames encrypted files using the following names:

  • {Base64-Encoded Filename and Extension}

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

  • {Encrypted File Path}\README_{7 Random Numbers}_{5 Random Numbers}.txt

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.532.08
FIRST VSAPI PATTERN DATE: 14 Jul 2017
VSAPI OPR PATTERN File: 13.533.00
VSAPI OPR PATTERN Date: 15 Jul 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\CurrentVersion\Policies\System
    • DisableTaskMgr = 1

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%\backup\BACKUP_2450318.txt
  • %Application Data%\delback.bat
  • {Encrypted File Path}\README_{7 Random Numbers}_{5 Random Numbers}.txt

Step 6

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

Restore encrypted files from backup.


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