Analysis by: Rheniel Rhay Ramos
ALIASES:

Trojan-Ransom.MSIL.Agent.goc (Kaspersky); Ransom.Koolova (Malwarebytes); Trojan:Win32/Tiggre!rfn (Microsoft)

 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.

  TECHNICAL DETAILS

File Size: 73,728 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 01 Nov 2017
Payload: Displays windows

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:

  • It will only continue its routines if the folder "%User Profile%\Documents\YES" exists
  • It will create a new desktop wherein the following window will be shown:
  • It will open the following window if the Deposit button is clicked:
  • If you input the following in the second window, the malware could be bypassed and you could simply press Decrypt to close it:

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.808.04
FIRST VSAPI PATTERN DATE: 01 Nov 2017
VSAPI OPR PATTERN File: 13.809.00
VSAPI OPR PATTERN Date: 02 Nov 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.H. 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.


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