RANSOM_BLOCKER.R00XC0OI517

 Analysis by: Rheniel Rhay Ramos

 ALIASES:

Ransom-Nulltica!B553D120875E (McAfee); Trojan-Ransom.Win32.Blocker.kgwu (Kaspersky); Ransom.HiddenTear!g1 (Symantec)

 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


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:

2,926,080 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

03 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 the following copies of itself into the affected system and executes them:

  • %Application Data%\{malware name}

(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 drops the following files:

  • %Application Data%\log.txt -> key for the encrypted files

(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 adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Global\ControlPanel

Autostart Technique

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

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Window = "%Application Data%\{malware name}"

Process Termination

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

  • iexplore
  • iexplorer
  • chrome
  • firefox
  • MicrosoftEdge

Other Details

This Ransomware connects to the following URL(s) to check for an Internet connection:

  • google.pl

It does the following:

  • It connects to the URL "http://bit.ly/2razNDz" which will then be redirected to "http://www.wikihow.com/Send-Bitcoins"
  • It tries to steal saved login credentials from the following browsers:
    • Chrome
    • Firefox
    • IE10
  • It opens the following URL then attempts to login the stolen credentials:
    • http://facebook.com/login.php
  • It lists all friends of the current account on Facebook and sends each one of them a message containing the malware and the following text:
    • To jest wiadomosc wyslana w calosci przez mojego bota
  • It adds the extension ".lock" to encrypted files then renames it back to the original file name during encryption.
  • It adds the extension ".unlock" to encrypted files then renames it back to the original file name during decryption.
  • It opens a GUI that serves as a ransom note:

  • It has the capability to decrypt the encrypted files once the ransom is paid.
  • It adds the following registry entry to disable the CTRL key:
    • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layout
      • Scancode Map = "0,0,0,0,0,0,0,0,3,0,0,0,0,0,29,0,0,0,29,224,0,0,0,0"

Ransomware Routine

This Ransomware encrypts files found in the following folders:

  • C:\Program Files (x86)
  • %Program Files%
  • %Application Data%
  • %Desktop%
  • {Removable Drives}

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.. %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.. %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.)

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

  • *.exe
  • *.lnk
  • Microsoft

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

  • Microsoft

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.641.06

FIRST VSAPI PATTERN DATE:

03 Sep 2017

VSAPI OPR PATTERN File:

13.642.00

VSAPI OPR PATTERN Date:

04 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\CurrentVersion\Run
    • Window = "%Application Data%\{malware name}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layout
    • Scancode Map = "0,0,0,0,0,0,0,0,3,0,0,0,0,0,29,0,0,0,29,224,0,0,0,0"

Step 5

Search and delete this file

[ 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%\log.txt

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_BLOCKER.R00XC0OI517. 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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