Analysis by: Earle Maui Earnshaw
ALIASES:

Trojan-Ransom.Win32.Snatch.d (Kaspersky); Ransom:Win64/Gocoder.P (Microsoft)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Ransomware drops files as ransom note. It avoids encrypting files with the following file extensions.

  TECHNICAL DETAILS

File Size: 4,234,240 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 11 Dec 2019
Payload: Displays message/message boxes, Encrypts files

Installation

This Ransomware adds the following processes:

  • vssadmin delete shadows /all /quiet → Delete all copies in the system
  • bcdedit.exe /set {current} safeboot minimal → To boot the system in safemode
  • shutdown /r /f /t 00 → restart the system immediately
  • net stop SuperBackupMan → after bootup into safe mode will stop the created service

Autostart Technique

This Ransomware adds and runs the following services:

  • Service Name: SuperBackupMan
    • Display Name: This service make backup copy every day
    • Image Path: {Malware Location}\{File Name}.exe is auto-started

Other System Modifications

This Ransomware adds the following registry keys:

HKLM\SYSTEM\CurrentControlSet\
Control\SafeBoot\Minimal\
SuperBackupMan
Default = Service

Other Details

This Ransomware does the following:

  • It affects all existing drives from A: to Z:
  • Checks the system if running in safe mode:
    • Will execute its ransomware routine if running and safe mode
    • If not, will reboot the system to run in safe mode to perform its ransomware routine
  • Should be executed under admin privileges to perform its malicious routine

Ransomware Routine

This Ransomware avoids encrypting files found in the following folders:

  • Directories located in %System Root%:
    • windows
    • perflogs
    • recovery
    • $recycle.bin
    Directories located in %ProgramData%:
    • microsoft
    • start menu
    • templates
    • favorites
    Directories located in %Program Files%:
    • uninstall information
    • mozilla maintenance service
    • microsoft.net
    • windows portable devices
    • windows sidebar
    • windows photo viewer
    • windows nt
    • windows media player
    • windows mail
    • windows journal
    • windows defender
    • tap-windows
    • reference assemblies
    • mozilla firefox
    • microsoft games
    • msbuild
    • internet explorer
    • dvd maker
    • common files
    • system volume information
    • $recycle.bin
    • perflogs
    • windows

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).)

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

  • .dglnl

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

  • RESTORE_DGLNL_FILES.txt

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

It avoids encrypting files with the following file extensions:

  • .exe
  • .dll
  • .sys
  • .ini

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 15.554.05
FIRST VSAPI PATTERN DATE: 12 Dec 2019
VSAPI OPR PATTERN File: 15.555.00
VSAPI OPR PATTERN Date: 13 Dec 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

Disable this malware service

[ Learn More ]
    • Service Name: SuperBackupMan
    • Image Path: {Malware Location}\{File Name}.exe is auto-started
    • Service Description: This service make backup copy every day

Step 5

Delete this registry key

[ 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\SYSTEM\CurrentControlSet\Control\SafeBoot\Minimal\SuperBackupMan
    • Default = Service

Step 6

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 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.SNATCH.B. 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 8

Restore encrypted files from backup.

Step 9

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.SNATCH.B. 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 the following Trend Micro Support pages for more information:


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