Analysis by: Homer Pacag
ALIASES:

Ransom.BadEncript (Malwarebytes); Trojan.Win32.DiskWriter.qx (Kaspersky);

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

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

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: 4,590,080 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 27 Dec 2016
Payload: Encrypts files, Drops 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.

Installation

This Trojan drops the following files:

  • {Malware Path}\!!! HOW TO DECRYPT FILES !!!.txt - ransom note

Other System Modifications

This Trojan modifies the following file(s):

  • It encrypts files and appends the extension .braincrypt

NOTES:

Below is the content of the ransom note !!! HOW TO DECRYPT FILES !!!.txt:

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 13.120.02
FIRST VSAPI PATTERN DATE: 27 Dec 2016
VSAPI OPR PATTERN File: 13.121.00
VSAPI OPR PATTERN Date: 27 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

Search and delete this file

[ 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.  
  • {Malware Path}\!!! HOW TO DECRYPT FILES !!!.txt

Step 4

Scan your computer with your Trend Micro product to delete files detected as RANSOM_BRAINCRYPT.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.


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