Analysis by: John Anthony Banes
ALIASES:

Ransom:Win32/Genasom (Microsoft); Mal/Crypdum-A (Sophos)

 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: 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. However, as of this writing, the said sites are inaccessible.

It encrypts files found in specific folders.

  TECHNICAL DETAILS

File Size: 37,376 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 19 Jun 2017
Payload: Connects to URLs/IPs, Displays windows, 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.

Other Details

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

  • http://{BLOCKED}an12.eu/cms/write.php?info={computer name}

However, as of this writing, the said sites are inaccessible.

Ransomware Routine

This Ransomware encrypts files found in the following folders:

  • %Desktop%

(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.)

NOTES:

The following window serves as the ransom note:

If the Depozytuj button is clicked, it displays another window:

Continue pressing ALT-TAB and ALT-F4 until the malware exits.

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.480.08
FIRST VSAPI PATTERN DATE: 19 Jun 2017
VSAPI OPR PATTERN File: 13.481.00
VSAPI OPR PATTERN Date: 20 Jun 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

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_DUMB.E. 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 3

Restore encrypted files from backup.


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