RANSOM_CERBER.VSAHBT

 Analysis by: Wilbert Vidal

 ALIASES:

Ransom:Win32/Cerber (MICROSOFT); Ransom.Cerber (NORTON)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


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.

  TECHNICAL DETAILS

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%\tmp{4 Alpha Numeric Characters}.bmp ← Ransom note wallpaper
  • %User Temp%\{random characters}\{random characters}.tmp

(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:

  • {folders containing encrypted files}\_R_E_A_D___T_H_I_S___{random characters}_.txt
  • {folders containing encrypted files}\_R_E_A_D___T_H_I_S___{random characters}_.hta

It creates the following folders:

  • %User Temp%\{8 random characters}

(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.)

Other System Modifications

This Ransomware changes the desktop wallpaper by modifying the following registry entries:

HKEY_CURRENT_USER
\Control Panel\Desktop Wallpaper = %User Temp%\tmp{random characters}.bmp

Other Details

This Ransomware connects to the following possibly malicious URL:

  • http://{BLOCKED}befuhenjp7.{BLOCKED}b.top/

It renames encrypted files using the following names:

  • {10 random characters}.{4 random characters}

It is capable of encrypting files in the affected system.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.560.03

FIRST VSAPI PATTERN DATE:

28 Jul 2017

VSAPI OPR PATTERN File:

13.561.00

VSAPI OPR PATTERN Date:

29 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

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Temp%\{8 random characters}

Step 4

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%\tmp{4 Alpha Numeric Characters}.bmp
  • {folders containing encrypted files}\_R_E_A_D___T_H_I_S___{random characters}_.txt
  • {folders containing encrypted files}\_R_E_A_D___T_H_I_S___{random characters}_.hta

Step 5

Reset your Desktop properties

[ Learn More ]

Step 6

Scan your computer with your Trend Micro product to delete files detected as RANSOM_CERBER.VSAHBT. 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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