RANSOM_MMM.A

February 06, 2018
 Analysis by: Christian Noel Olalia
 ALIASES:

HEUR:Trojan-Ransom.Win32.Generic (KASPERSKY); Trojan.Gen.2 (NORTON); Mal/TripM-A (SOPHOS_LITE)

 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 executes then deletes itself afterward.

It encrypts files with specific file extensions. It drops files as ransom note.

  TECHNICAL DETAILS

File Size:

32,256 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

03 Jan 2018

Payload:

Encrypts files, 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%\changelog.txt - contains information that OS is simulating
  • {malware path}\key_{random 8 characters}.{random 3 characters}.mmm - contains the RSA key value

(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%\temp_1.bat - quietly delete all shadow volume copies
  • %Application Data%\reco.bat - disables Windows recovery mode
  • %Application Data%\bcedit.bat - disables Windows startup repair

(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 executes then deletes itself afterward.

Other Details

This Ransomware does the following:

  • Execute the following commands:
    • vssadmin.exe delete shadows /all /quiet
    • bcdedit.exe /set {default} recoveryenabled No
    • bcdedit.exe /set {default} bootstatuspolicy ignoreallfailures
  • RESTORE_triple_m__FILES.html displays the following:

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .dis
  • .adx
  • .fp7
  • .sif
  • .ldf
  • .ndf
  • .mdf
  • .trn
  • .err
  • .pdf
  • .myi
  • .myd
  • .zip
  • .bak
  • .bkf
  • .prn
  • .data
  • .ctf
  • .mkd
  • .ziz
  • .pxf
  • .dst
  • .eps
  • .tlf
  • .ltf
  • .cdr
  • .pmd
  • .ai
  • .txt
  • .qbw
  • .qbb
  • .tlg
  • .ecw
  • .pdf
  • .frm
  • .pix
  • .accdb
  • .mdb
  • .cdr
  • .eps
  • .tif
  • .msg
  • .asmx
  • .rpt
  • .arw
  • .qbo
  • .qbw
  • .sldprt
  • .dwf
  • .doc
  • .adi
  • .adt
  • .docx
  • .altr
  • .xls
  • .xlsx
  • .ppt
  • .pptx
  • .odt
  • .jpg
  • .png
  • .csv
  • .sql
  • sln
  • .php
  • .asp
  • .aspx
  • .html
  • .xml
  • .psd
  • .bat
  • .js
  • .css
  • .sqlite
  • .dwg
  • .jpeg

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

  • .triple_m
  • .info

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

  • {Encrypted file path}\RESTORE_triple_m__FILES.html

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.882.04

FIRST VSAPI PATTERN DATE:

03 Jan 2018

VSAPI OPR PATTERN File:

13.883.00

VSAPI OPR PATTERN Date:

04 Jan 2018

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_MMM.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 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.
  • {Encrypted file path}\RESTORE_triple_m__FILES.html

Step 5

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

Restore encrypted files from backup.

NOTES:

  1. Enable services disabled using the command prompt.
  2. Run cmd.exe as administrator.
  3. To enable Windows Error Recovery Screen on Startup use the following command: bcdedit /set {default} bootstatuspolicy displayallfailures
  4. To enable Startup Repair use the following command: /bcedit /set {default} recoveryenabled Yes


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