Analysis by: John Rey Canon
ALIASES:

Trojan.Ransom.Zyka (ALYac); MSIL/StupCryp.A!tr (Fortinet)

 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 is capable of encrypting files in the affected system.

It encrypts files found in specific folders.

  TECHNICAL DETAILS

File Size: 69,645 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 03 Dec 2018
Payload: 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.

Autostart Technique

This Ransomware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
DO NOT OPEN THE FUCKIN RANSOMWARE = {Malware Path}\{Malware Filename}.exe

Other Details

This Ransomware does the following:

  • It displays the following window while encrypting files:
  • It displays the following window after encrypting files as ransom note:

It is capable of encrypting files in the affected system.

Ransomware Routine

This Ransomware encrypts files found in the following folders:

  • %All Users Profile%
  • %User Profile%\Documents
  • %User Profile%\Music
  • %User Profile%\Pictures
  • %User Profile%\Downloads
  • %Desktop%
  • %System Root%\
  • %Windows%
  • %System Root%\Documents

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000, XP, and Server 2003, or C:\ProgramData on Windows Vista, 7, and 8. . %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista, 7, and 8.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista, 7, and 8.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

It appends the following extension to the file name of the encrypted files:

  • .lock

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.670.05
FIRST VSAPI PATTERN DATE: 06 Dec 2018
VSAPI OPR PATTERN File: 14.671.00
VSAPI OPR PATTERN Date: 07 Dec 2018

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

Restart in Safe Mode

[ Learn More ]

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.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • DO NOT OPEN THE FUCKIN RANSOMWARE = {Malware Path}\{Malware Filename}.exe

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.ZYKA.THABOFAH. 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.

Step 7

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.ZYKA.THABOFAH. 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:


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