➔
search
✕

RANSOM_MYSTIC.A

October 13, 2017
 Analysis by: Rheniel Rhay Ramos
 ALIASES:

Ransom.FileLocker (Malwarebytes); Backdoor.Graybird (Symantec); Backdoor.Graybird (Norton)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • 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 connects to certain websites to send and receive information.

It encrypts files found in specific folders. It drops files as ransom note.

  TECHNICAL DETAILS

File Size:

62,976 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

11 Sep 2017

Payload:

Connects to URLs/IPs, Drops files, 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:

  • notepad.exe "%Desktop%\ransom.txt"

(Note: %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 System Modifications

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

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = ""

Other Details

This Ransomware connects to the following website to send and receive information:

  • http://{BLOCKED}ker.tk/track/6.1/1001

It drops the following file(s)/component(s):

  • %AppDataLocal%{File to be Encrypted} -> temporary file used for encryption (deleted afterwards)

(Note: %AppDataLocal% is the Application Data folder found in Local Settings, where it is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local 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:

  • %User Profile%\Videos
  • %User Profile%\Pictures
  • %User Profile%\Music
  • %User Profile%\Documents
  • %Desktop%

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %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 drops the following file(s) as ransom note:

  • %Desktop%\ransom.txt

(Note: %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 leaves text files that serve as ransom notes containing the following text:

  • Your computer has been hacked and your files have been locked.

    You have 5 days left to recover your files so quickly follow recovery process below.

    Recovery Process in 3 easy steps (Automated System. No human intervention. Works 24/365):

    1) Buy 1.01 BitCoin Approx 280$. (Easiest buying option is www.localbitcoins.com) and go to the following website:

    http://{BLOCKED}ybsm6hk72j.onion.cab/pay/kL5QHL378+zjWv1LuaJobm3jzCzS8ydtKl2zJ78WPQpx+uUpkac9G0TVtjjSiD5mmwg3xde6J+2xdet6ejeCx0W8RpraMD91e0NFe4mWA*HtsIl+lL490hFtxLjmZ1giTgR1RRoQmbEMYVFMd6vu71wyyLhN6WeTLH4VHiZI7dW5zCpTdmkXUr3HYsmN057DjsWS8M38xaI3IL9pSEuamhMTQgMHNB7kIJ95mBIylKFdb6qb9eaq*tUiM*ngLAxcTQKWLpxuBus2A800RVm9uCeqdDIJ9t2gGhEuk8DIVHue1SwpcOTWdBZoguPRtxMpjEeg6UZ+wo8WOBZtW+3ioQ==

    2) Send payment of 1.01 Bitcoin to the address in the website given above.

    3) In approx 15 minutes after making the payment to the bitcoin address, Go back to the above website. If payment is successful then you will receive unlock instructions.

    Don't delete or modify this ransom file till recovery of files as no recovery is possible without this file. This file is on your desktop for future use.

    List of files which have been locked are given below.
    -- MYSTIC

    {Personal ID}

    {List of Encrypted Files...
    ...
    ...}

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.656.08

FIRST VSAPI PATTERN DATE:

11 Sep 2017

VSAPI OPR PATTERN File:

13.657.00

VSAPI OPR PATTERN Date:

12 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

Identify and terminate files detected as RANSOM_MYSTIC.A

[ 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

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.  
  • %Desktop%\ransom.txt
  • %AppDataLocal%{File to be Encrypted}

Step 5

Scan your computer with your Trend Micro product to delete files detected as RANSOM_MYSTIC.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 6

Reset your Desktop properties

[ Learn More ]

Step 7

Restore encrypted files from backup.


Did this description help? Tell us how we did.