Ransom.MSIL.CRYPTEAR.A

July 24, 2019
 Analysis by: John Anthony Banes
 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:

Downloaded from the Internet, Dropped by other malware

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. It deletes itself after execution.

It encrypts files with specific file extensions. It drops files as ransom note.

  TECHNICAL DETAILS

File Size:

120,320 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

23 Jul 2019

Payload:

Connects to URLs/IPs, Displays windows, Displays message/message boxes

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 a copy of itself in the following folders using different file names:

  • %System Root%\{username}\Systems\local.exe

(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%\{username}\Systems
  • %System Root%\{username}

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

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Systems = "%System Root%\{username}\Decrypter.exe"

Download Routine

This Ransomware connects to the following website(s) to download and execute a malicious file:

  • http://{BLOCKED}agy.ru/Decrypter.exe
  • http://{BLOCKED}agy.ru/ransom.jpg

It saves the files it downloads using the following names:

  • %Desktop%\Decrypter.exe - Ransomware Decrypt screen
  • %System Root%\{username}\ransom.jpg - Wallpaper
  • %System Root%\{username}\Decrypter.exe - Ransomware Decrypt screen

(Note: %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\Desktop on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

Other Details

This Ransomware connects to the following URL(s) to check for an Internet connection:

  • https://maper.info/XGnV6

It connects to the following website to send and receive information:

  • http://{BLOCKED}agy.ru/write.php?computer_name={computer name}&userName={username}&password={15 random characters}&allow=ransom

It deletes itself after execution.

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .001
  • .7-zip
  • .ace
  • .apk
  • .arj
  • .asp
  • .aspx
  • .avi
  • .bmp
  • .bz2
  • .c
  • .cab
  • .contact
  • .core
  • .cpp
  • .crproj
  • .cs
  • .csv
  • .dat
  • .db
  • .dll
  • .doc
  • .docx
  • .dwg
  • .exe
  • .f3d
  • .gzip
  • .htm
  • .html
  • .ico
  • .iso
  • .jar
  • .jpg
  • .lnk
  • .lzh
  • .mdb
  • .mkv
  • .mov
  • .mp3
  • .mp3
  • .mp4
  • .mpeg
  • .mpg
  • .odt
  • .pas
  • .pdb
  • .pdf
  • .php
  • .png
  • .ppt
  • .pptx
  • .psd
  • .py
  • .rar
  • .rtf
  • .settings
  • .sln
  • .sql
  • .tar
  • .torrent
  • .txt
  • .uue
  • .xls
  • .xlsx
  • .xml
  • .xz
  • .z
  • .zip

It renames encrypted files using the following names:

  • {encrypted file}.Pox

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

  • %Desktop%\HOW TO DECRYPT FILES.txt

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

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

NOTES:
Decrypter.exe displays the following window:

  SOLUTION

Minimum Scan Engine:

9.850

VSAPI OPR PATTERN File:

15.251.00

VSAPI OPR PATTERN Date:

24 Jul 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

Identify and terminate files detected as Ransom.MSIL.CRYPTEAR.A

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
  • Systems = "%System Root%\{username}\Decrypter.exe"

Step 5

Search and delete this folder

[ 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%\{username}
  • %System Root%\{username}\Systems

Step 6

Search and delete these files

[ 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.
  • %Desktop%\Decrypter.exe
  • %Desktop%\HOW TO DECRYPT FILES.txt
  • %System Root%\{username}\ransom.jpg
  • %System Root%\{username}\Decrypter.exe

Step 7

Scan your computer with your Trend Micro product to delete files detected as Ransom.MSIL.CRYPTEAR.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 8

Reset your Desktop properties

[ Learn More ]

Step 9

Restore encrypted files from backup.


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