Analysis by: Earle Maui Earnshaw
ALIASES:

Trojan-Ransom.Win32.Encoder.bmd (Kaspersky); Ransom:Win32/Clop.A!MTB (Microsoft)

 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 drops files as ransom note.

  TECHNICAL DETAILS

File Size: 102,912 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 12 Feb 2019
Payload: Terminates processes, Drops 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 adds the following mutexes to ensure that only one of its copies runs at any one time:

  • CLOP#666

Process Termination

This Ransomware terminates the following processes if found running in the affected system's memory:

  • zoolz.exe
  • mysqld-nt.exe
  • syntime.exe
  • agntsv.exe
  • mysqld-opt.exe
  • tbirdonfig.exe
  • dbeng50.exe
  • oautoupds.exe
  • thebat.exe
  • dbsnmp.exe
  • oomm.exe
  • thebat64.exe
  • ensv.exe
  • ossd.exe
  • thunderbird.exe
  • exel.exe
  • onenote.exe
  • visio.exe
  • firefoxonfig.exe
  • orale.exe
  • winword.exe
  • infopath.exe
  • outlook.exe
  • wordpad.exe
  • isqlplussv.exe
  • powerpnt.exe
  • xfssvon.exe
  • msaess.exe
  • sqboreservie.exe
  • tmlisten.exe
  • msftesql.exe
  • sqlagent.exe
  • PNTMon.exe
  • mspub.exe
  • sqlbrowser.exe
  • NTAoSMgr.exe
  • mydesktopqos.exe
  • sqlservr.exe
  • Ntrtsan.exe
  • mydesktopservie.exe
  • sqlwriter.exe
  • mbamtray.exe
  • mysqld.exe
  • steam.exe
  • zoolz.exe
  • mysqld-nt.exe
  • syntime.exe
  • agntsv.exe
  • mysqld-opt.exe
  • tbirdonfig.exe
  • dbeng50.exe
  • oautoupds.exe
  • thebat.exe
  • dbsnmp.exe
  • oomm.exe
  • thebat64.exe
  • ensv.exe
  • ossd.exe
  • thunderbird.exe
  • exel.exe
  • onenote.exe
  • visio.exe
  • firefoxonfig.exe
  • orale.exe
  • winword.exe
  • infopath.exe
  • outlook.exe
  • wordpad.exe
  • isqlplussv.exe
  • powerpnt.exe
  • xfssvon.exe
  • msaess.exe
  • sqboreservie.exe
  • tmlisten.exe
  • msftesql.exe
  • sqlagent.exe
  • PNTMon.exe
  • mspub.exe
  • sqlbrowser.exe
  • NTAoSMgr.exe
  • mydesktopqos.exe
  • sqlservr.exe
  • Ntrtsan.exe
  • mydesktopservie.exe
  • sqlwriter.exe
  • mbamtray.exe
  • mysqld.exe
  • steam.exe

Other Details

This Ransomware does the following:

  • Encrypts files that can be found in the following drive types:
    • Fixed Drives
    • Removable Drives
    • Network Drives
  • Will Encrypt all files and directories except those containing the following strings:
    • Chrome
    • Mozilla
    • Recycle.bin
    • Microsoft
    • AhnLab
    • Windows
    • All Users
    • ProgramData
    • Program Files (x86)
    • PROGRAM FILES (X86)
    • Program Files
    • PROGRAM FILES
    • Desktop
    • DESKTOP
  • Will encrypt all file types exept the files/extensions that contains the following strings:
    • ClopReadMe.txt
    • ntldr
    • NTLDR
    • boot.ini
    • BOOT.INI
    • ntuser.ini
    • NTUSER.INI
    • AUTOEXEC.BAT
    • autoexec.bat
    • .Clop
    • NTDETECT.COM
    • ntdetect.com
    • .dll
    • .DLL
    • .exe
    • .EXE
    • .sys
    • .SYS
    • .OCX
    • .ocx
    • .LNK
    • .lnk
  • After 300 seconds will encrypt the directory that contains the malicious file.

Ransomware Routine

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

  • {File Name}.{File Extension}.Clop

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

  • {Encrypted Directory}\ClopReadMe.txt

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.808.02
FIRST VSAPI PATTERN DATE: 12 Feb 2019
VSAPI OPR PATTERN File: 14.809.00
VSAPI OPR PATTERN Date: 13 Feb 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

Restart in Safe Mode

[ Learn More ]

Step 4

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.  
  • {Encrypted Directory}\ClopReadMe.txt

Step 5

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


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