Analysis by: Marvelous Pelin
ALIASES:

RDN/Ransom(McAfee);Ransom:Win32/Genasom(Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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.

  TECHNICAL DETAILS

File Size: 348,160 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 19 Dec 2016
Payload: 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 keys as part of its installation routine:

HKEY_CURRENT_USER\Software\MyRansomWare

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\MyRansomWare\
AppVersion
Created By = Shtein Solutions

HKEY_CURRENT_USER\Software\MyRansomWare\
AppVersion
Description = Ransomware POC for Penetration Testing

HKEY_CURRENT_USER\Software\MyRansomWare\
AppVersion
encKey = {random values}

Other Details

This Trojan renames encrypted files using the following names:

  • {original filename and extension}.enc

It does the following:

  • It encrypts files in %User Profile%\Documents path.
  • Before encrypting a file, it creates a copy of the file then encrypt the created copy. It does not encrypt the original copy.

(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.)

NOTES:

This ransomware displays the following after execution.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.940.03
FIRST VSAPI PATTERN DATE: 19 Dec 2016
VSAPI OPR PATTERN File: 12.941.00
VSAPI OPR PATTERN Date: 20 Dec 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

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry key

[ 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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

 
  • In HKEY_CURRENT_USER\Software
    • MyRansomWare

Step 5

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

Restore encrypted files from backup.


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