Analysis by: Byron Jon Gelera

 ALIASES:

Ransom:Win32/Pocrimcrypt.A (Microsoft); Trojan-Ransom.Win32.Autoit.lc (Kaspersky); Win32/Filecoder.NGX(ESET-NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

RANSOM_MIRCOP.F116IL is a variant of RANSOM_MIRCOP.A, a ransomware that uses the image of Guy Fawkes to scare victims. Besides encrypting user files, the ransom note tells users that they have stolen from the notorious hacktivist group which use the image to mask their identity.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

This Trojan 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

File Size: 858,398 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 22 Sep 2016
Payload: Displays message/message boxes, Encrypts files

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %User Temp%\wl.jpg

It sets the system's desktop wallpaper to the following image:

Other Details

This Trojan renames encrypted files using the following names:

  • Lock.{original filename and extension}

It is capable of encrypting files in the affected system.

NOTES:

This ransomware only encrypts files in the following folders:

  • %Desktop%
  • %User Profile%\Music
  • %User Profile%\Pictures
  • %User Profile%\Videos
  • %User Profile%\Documents
  • C:\Users\Public\Documents
  • C:\Users\Public\Pictures
  • C:\Users\Public\Videos

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.790.08
FIRST VSAPI PATTERN DATE: 21 Sep 2016
VSAPI OPR PATTERN File: 12.791.00
VSAPI OPR PATTERN Date: 22 Sep 2016

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

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\Control Panel\Desktop
    • Wallpaper = "%User Temp%\wl.jpg"

Step 4

Scan your computer with your Trend Micro product to delete files detected as RANSOM_MIRCOP.F116IL. 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 5

Restore encrypted files from backup.


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