Ransom.Win32.TRIPLEM.THCBGAI

May 01, 2019
 Modified by: Earle Maui Earnshaw
 ALIASES:

Trojan:Win32/Occamy.B(Microsoft); Trojan.PWS.Banker1.30223(DrWeb)

 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

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 deletes itself after execution.

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

  TECHNICAL DETAILS

File Size:

36,864 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

26 Mar 2019

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:

  • {Malware Directory}\{8 Random Characters}.{3 Random Characters}.exe
  • {Malware Directory}\ecorp.bat

It adds the following processes:

  • cmd.exe /C vssadmin.exe delete shadows /all /Quiet -> deletes all shadow copies
  • cmd.exe /C WMIC.exe shadowcopy delete -> deletes all shadow copies
  • cmd.exe /C Bcdedit.exe /set {default} recoveryenabled no -> Disables Windows Recovery on Startup
  • cmd.exe /C Bcedit.exe /set {default} bootstatuspolicy ignoreallfailures -> disable system's trigger to call the Error Recovery screen on startup
  • cmd.exe /c "{Malware Directory}\ecorp.bat" -> Delete malware
  • cmd.exe /c wevtutil.exe cl Security
  • cmd.exe /c wevtutil.exe cl System
  • cmd.exe /c wevtutil.exe cl Application

Other Details

This Ransomware deletes itself after execution.

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .accdb
  • .adi
  • .adt
  • .ADX
  • .adx
  • .ai
  • .altr
  • .arw
  • .asmx
  • .asp
  • .aspx
  • .bak
  • .bat
  • .bkf
  • .cdr
  • .cdr
  • .css
  • .csv
  • .ctf
  • .data
  • .DBF
  • .dis
  • .doc
  • .docx
  • .dst
  • .dwf
  • .dwg
  • .ecw
  • .eps
  • .eps
  • .err
  • .fbk
  • .FBK
  • .fp7
  • .FP7
  • .frm
  • .html
  • .jpeg
  • .JPG
  • .jpg
  • .js
  • .LDF
  • .ldf
  • .ltf
  • .mdb
  • .MDF
  • .mdf
  • .mkd
  • .msg
  • .myd
  • .myi
  • .ndf
  • .odt
  • .pdf
  • .pdf
  • .PDF
  • .php
  • .pix
  • .pmd
  • .png
  • .ppt
  • .pptx
  • .prn
  • .psd
  • .pxf
  • .QBB
  • .qbb
  • .qbo
  • .qbw
  • .QBW
  • .qbw
  • .rpt
  • .sldprt
  • .sln
  • .sql
  • .sqlite
  • .sVn
  • .svn
  • .tif
  • .tlf
  • .TLG
  • .tlg
  • .trn
  • .txt
  • .xls
  • .xlsx
  • .xml
  • .zip
  • .ziz

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

  • ProgramData
  • Program Files
  • Pictures
  • Music
  • Package Cache
  • VMware
  • \Microsoft\
  • Appdata
  • Activators
  • Program Files (x86)
  • Windows
  • Program Data
  • All Users
  • Users\Default

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

  • {Encrypted Directory}\DECRYPT_FILES.txt

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

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.899.00

FIRST VSAPI PATTERN DATE:

27 Mar 2019

VSAPI OPR PATTERN File:

14.900.00

VSAPI OPR PATTERN Date:

28 Mar 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}\DECRYPT_FILES.txt
  • {Malware Directory}\{8 Random Characters}.{3 Random Characters}.exe
  • {Malware Directory}\ecorp.bat

Step 5

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