Ransom.MSIL.MINOTAUR.THAOAEAH

November 05, 2018
 Analysis by: Michael Jhon Ofiaza
 ALIASES:

Ransom:MSIL/Mrynimal (Microsoft) ; HEUR:Trojan-Ransom.MSIL.Crypmod.gen (Kaspersky)

 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 drops files as ransom note.

  TECHNICAL DETAILS

File Size:

11,776 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

03 Oct 2018

Payload:

Drops 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.

Other Details

This Ransomware does the following:

  • Encrypts all Drives
  • Avoids encrypting files with the following attribute:
    • System
    • Hidden
    • ReadOnly
  • Avoids encrypting all files with .Lock extension

Ransomware Routine

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

  • autoexec.bat
  • config.sys
  • ntuser.dat
  • ntdata.dat

It avoids encrypting files found in the following folders:

  • windows
  • system volume information
  • $recycle.bin
  • windows.old

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

  • .Lock

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

  • {Encrypted Folder}\How To Decrypt Files.txt

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.608.03

FIRST VSAPI PATTERN DATE:

05 Nov 2018

VSAPI OPR PATTERN File:

14.609.00

VSAPI OPR PATTERN Date:

06 Nov 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

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.  
  • {Encrypted Folder}\How To Decrypt Files.txt

Step 4

Scan your computer with your Trend Micro product to delete files detected as Ransom.MSIL.MINOTAUR.THAOAEAH. 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 5

Restore encrypted files from backup.


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