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RANSOM_DARKLOCKER.A

April 03, 2017
 Analysis by: John Anthony Banes
 ALIASES:

Trojan:Win32/Skeeyah.A!rfn (Microsoft); a variant of MSIL/Kryptik.IDS trojan (NOD32); MSIL/Kryptik.IDS!tr (Fortinet)

 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:

Dropped by other malware, 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.

  TECHNICAL DETAILS

File Size:

1,450,496 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

23 Mar 2017

Payload:

Connects to URLs/IPs, 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 modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "can.exe, winlk.exe"

(Note: The default value data of the said registry entry is "explorer.exe".)

Other Details

This Ransomware does the following:

  • It executes the following commands to shutdown the system within 4 minutes:
    shutdown -s -t 240
  • It connects to the following URL for stat counter:
    cryptot24-001-site1.{BLOCKED}rl.com/main.html

NOTES:

This ransomware does not encrypt any file in the affected computer. Instead it displays the following lockscreen:

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.296.02

FIRST VSAPI PATTERN DATE:

24 Mar 2017

VSAPI OPR PATTERN File:

13.297.00

VSAPI OPR PATTERN Date:

25 Mar 2017

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

Restore this modified 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 NT\CurrentVersion\Winlogon
    • From: Shell = "can.exe, winlk.exe"
      To: Shell = "explorer.exe"

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_DARKLOCKER.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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