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Ransom.Win32.LOCKERGOGA.THBOGAI

March 15, 2019
 Analysis by: Jay Bradley Nebre
 ALIASES:

Trojan-Ransom.LockerGoga(IKARUS); Win32/Filecoder.LockerGoga.B trojan(NOD32)

 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 encrypts files with specific file extensions.

  TECHNICAL DETAILS

File Size:

1,274,736 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

07 Feb 2019

Payload:

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 drops a copy of itself in the following folders using different file names:

  • %User Temp%\hvwfcsky{4-5 random numbers}.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.)

It adds the following processes:

  • %User Temp%\hvwfcsky{4-5 random numbers}.exe -w (if no parameter)

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.)

Other Details

This Ransomware accepts the following parameters:

  • -w = allows encryption of all file types
  • -v = display version
  • -h = help message
  • -m = email used in ransom note
  • -e = erase file
  • -l = create log file
  • -j = allow multi threading
  • -f = input file
  • -r = dry run
  • {filename} -w = encrypt a specific file

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .doc
  • .dot
  • .docx
  • .docb
  • .dotx
  • .dotb
  • .wbk
  • .xlm
  • .xlsx
  • .xltx
  • .xlsb
  • .xlw
  • .ppt
  • .pps
  • .pot
  • .potx
  • .ppsx
  • .pptx
  • .sldx
  • .pdf
  • .db
  • .sql

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

  • .locked

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

  • READ-ME-NOW.txt

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.798.05

FIRST VSAPI PATTERN DATE:

07 Feb 2019

VSAPI OPR PATTERN File:

14.799.00

VSAPI OPR PATTERN Date:

08 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 these files

[ 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.
  • %User Temp%\hvwfcsky{4-5 random numbers}.exe
  • READ-ME-NOW.txt

Step 5

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