Analysis by: Earle Maui Earnshaw
ALIASES:

Trojan.MSIL.KillFiles.d (Kaspersky); Trojan:Win32/Occamy.C (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: 45,056 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 27 Feb 2019
Payload: Encrypts files, Connects to URLs/IPs, Downloads files, Displays graphics/image

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.

Installation

This Trojan drops and executes the following files:

  • %System Root%\memes\Idiot.exe - Displays the image downloaded from the URL.

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It creates the following folders:

  • %System Root%\memes

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

Other Details

This Trojan does the following:

  • Overwrites the files with the following contents:
  • Displays the following:
  • Connects to the following URL to download a file:
    • https://cdn.{BLOCKED}dapp.com/attachments/548593284985913388/548621341654515783/despacito.gif
  • It requires the following arguments to perform its malicious routine:
    • /K
  • Overwrites files in all drives.

Ransomware Routine

This Trojan appends the following extension to the file name of the encrypted files:

  • {File Name}.{File Extension}.txt

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.894.04
FIRST VSAPI PATTERN DATE: 25 Mar 2019
VSAPI OPR PATTERN File: 14.895.00
VSAPI OPR PATTERN Date: 26 Mar 2019

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 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

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.  
  • %System Root%\memes

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Trojan.MSIL.DOGOJOKER.THBBGAI. 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.


Did this description help? Tell us how we did.