Analysis by: Clive Fuentebella

ALIASES:

Ransom:Win32/FileCoder.CH!MTB (MICROSOFT)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: 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 drops files as ransom note.

  TECHNICAL DETAILS

File Size: 937,984 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 07 Jul 2020
Payload: Displays message/message boxes, 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.

Installation

This Ransomware drops the following copies of itself into the affected system:

  • %User Profile%\Documents\csrsse.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Other Details

This Ransomware does the following:

  • It does not execute if %User Profile%\Documents\csrsse.exe is found on the system.

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Ransomware Routine

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

  • .52pojie

It drops the following file(s) as ransom note:

  • {Encrypted directory}\52pojie-DECRYPT----{Random number}.txt

It leaves text files that serve as ransom notes containing the following text:

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 15.976.04
FIRST VSAPI PATTERN DATE: 07 Jul 2020
VSAPI OPR PATTERN File: 15.977.00
VSAPI OPR PATTERN Date: 08 Jul 2020

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

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.
  • %User Profile%\Documents\csrsse.exe

Step 4

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.POJIE.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 the following Trend Micro Support pages for more information:

Step 5

Restore encrypted files from backup.


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