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Ransom.Win32.OUROBOROS.B

May 01, 2020
 ALIASES:

Ransom:Win32/Ouroboros.GG!MTB (MICROSOFT); Trojan-Ransom.Win32.Gen.wnl (KASPERSKY)

 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 encrypts files found in specific folders. It drops files as ransom note.

  TECHNICAL DETAILS

File Size:

1,021,440 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

15 Apr 2020

Payload:

Displays message/message boxes, Encrypts files, Disables services, Terminates processes, Connects to URLs/IPs

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:

  • %All Users Profile%\IDo.txt -> contains ID
  • %All Users Profile%\pubkey.txt -> contains key

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

It adds the following processes:

  • cmd.exe /c netsh advfirewall set currentprofile state off
  • cmd.exe /c netsh firewall set opmode mode=disable
  • cmd.exe /c bcdedit /set {default} bootstatuspolicy ignoreallfailures
  • cmd.exe /c bcdedit /set {default} recoveryenabled no
  • cmd.exe /c wbadmin delete catalog -quiet
  • vssadmin delete shadows /all

Process Termination

This Ransomware terminates the following services if found on the affected system:

  • SQLWriter
  • SQLBrowser
  • MSSQLSERVER
  • MSSQL$CONTOSO1
  • MSDTC
  • SQLSERVERAGENT
  • vds

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

  • sqlserver.exe
  • msftesql.exe
  • sqlagent.exe
  • sqlbrowser.exe
  • sqlwriter.exe
  • mysqld.exe
  • mysqld-nt.exe
  • mysqld-opt.exe

Stolen Information

This Ransomware sends the gathered information via HTTP POST to the following URL:

  • http://{BLOCKED}.{BLOCKED}.69.52 -> the key, IP address, and unique ID of the user is sent

Other Details

This Ransomware connects to the following URL(s) to get the affected system's IP address:

  • http://www.sfml-dev.org/ip-provider.php

Ransomware Routine

This Ransomware encrypts files found in the following folders:

  • Fixed, removable, and network drives

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

  • .[xtredboy@protonmail.com][ID-{unique ID}].Void

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

  • %Program Files%\Decryption-Info.HTA {ouroboros_note.png}

(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).)

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.840.01

FIRST VSAPI PATTERN DATE:

30 Apr 2020

VSAPI OPR PATTERN File:

15.841.00

VSAPI OPR PATTERN Date:

01 May 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.XXPE50FFF035

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 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.
  • %All Users Profile%\IDo.txt
  • %All Users Profile%\pubkey.txt
  • %Program Files%\Decryption-Info.HTA

Step 6

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

Enabling Windows Error Recovery

  1. Run the command prompt (cmd.exe) as administrator.
  2. Enable Windows Error Recovery Screen on Startup by typing the following command:
    bcdedit /set {default} bootstatuspolicy displayallfailures

Step 9

Enabling Startup Repair

  1. Run the command prompt (cmd.exe) as administrator.
  2. Enable Startup Repair by typing the following command:
    /bcedit /set {default} recoveryenabled Yes

Step 10

Restore encrypted files from backup.


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