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Ransom.Win32.LOCKCRYPT.EKNAJ

January 09, 2020
 Analysis by: Jay Bradley Nebre
 ALIASES:

a variant of Win32/Filecoder.NPA trojan(NOD32)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 INFORMATION EXPOSURE:

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • 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:

11,264 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

04 Jan 2020

Payload:

Encrypts files, 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 the following files:

  • %Windows%\ncler.txt
  • %Windows%\searchfiles.exe - copy of itself

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

It adds the following processes:

  • %System%\cmd.exe /c vssadmin delete shadows /all

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
unlock = "%System Root%\How To Decode Files.hta"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
searchfiles = %Windows%\searchfiles.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\DateTime
orsa = {Hex Value}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\DateTime
rsa = {Hex Value}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.BadNews\shell\open\
command
(Default) = %System%\mshta.exe "%System Root%\How To Decode Files.hta"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer
GlobalAssocChangedCounter = 57

Other Details

This Ransomware does the following:

  • Terminates all process found that are not included in the following:
    • [System process]
    • System
    • smss.exe
    • dllhost.exe
    • svchost.exe
    • csrss.exe
    • Microsoft
    • ActiveDirectory
    • WebServices.exe
    • cmd.exe
    • mstsc.exe
    • find.exe
    • conhost.exe
    • explorer.exe
    • ctfmon.exe
    • lsass.exe
    • services.exe
    • tasklist.exe
    • winlogon.exe
    • wmiprvse.exe
    • msdts.exe
    • bfsvc.exe
    • AdapterTroubleshooter.exe
    • alg.exe
    • dwm.exe
    • issch.exe
    • rundll32.exe
    • spoolsv.exe
    • wininit.exe
    • wmiprvse.exe
    • wudfhost.exe
    • taskmgr.exe
    • rdpclip.exe
    • logonui.exe
    • lsm.exe
    • searchui.exe
    • searchindexer.exe
    • processhacker.exe
    • getpassvord_x64.exe
    • 64.exe
    • 32.exe
    • mshta.exe
    • fontdrvhost.exe
    • sihost.exe
    • pscan24.exe
    • advanced_port_scanner.exe
    • advanced_port_scanner_console.exe
    • pscan24
    • tmp
    • dfssvc.exe

Ransomware Routine

This Ransomware avoids encrypting files with the following strings in their file name:

  • How to Decode Files.hta
  • .BadNews

It avoids encrypting files with the following strings in their file path:

  • windows

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

  • {Original Filename} ID {Random ID}.BadNews

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

  • {Encrypted Directory}\How To Decode Files.hta

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.608.07

FIRST VSAPI PATTERN DATE:

08 Jan 2020

VSAPI OPR PATTERN File:

15.609.00

VSAPI OPR PATTERN Date:

09 Jan 2020

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

     Troj.Win32.TRX.XXPE50FFF033

Step 2

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 3

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 4

Restart in Safe Mode

[ Learn More ]

Step 5

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.
  • %Windows%\searchfiles.exe
  • %Windows%\ncler.txt

Step 6

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
    • unlock = "%System Root%\How To Decode Files.hta"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • searchfiles = %Windows%\searchfiles.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\DateTime
    • orsa = {Hex Value}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\DateTime
    • rsa = {Hex Value}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.BadNews\shell\open\command
    • (Default) = %System%\mshta.exe "%System Root%\How To Decode Files.hta"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer
    • GlobalAssocChangedCounter = 57

Step 7

Enabling Volume Shadow Service

  1. Run the command prompt (cmd.exe) as administrator.
  2. Enable Volume Shadow Service by typing the following command:
    net start vss

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.LOCKCRYPT.EKNAJ. 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 9

Restore encrypted files from backup.


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