Analysis by: John Rainier Navato

ALIASES:

a variant of Win64/Spy.Ursnif.AR trojan (NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This Backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 58,368 bytes
File Type: DLL
Memory Resident: No
Initial Samples Received Date: 29 Nov 2024
Payload: Connects to URLs/IPs, Collects system information, Executes commands

Arrival Details

This Backdoor 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 Backdoor adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Global\{Two Registry Key Names Found from HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control}

Backdoor Routine

This Backdoor executes the following commands from a remote malicious user:

  • Execute arbitrary commands

It connects to the following websites to send and receive information:

  • https://{BLOCKED}xt.top/index.html

However, as of this writing, the said sites are inaccessible.

Information Theft

This Backdoor gathers the following data:

  • Checksum of username
  • Cheksum of creation time of %System Root%\pagefile.sys or %System Root%\hiberfil.sys
  • Checksum of malware file name
  • Checksum of malware file

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

Other Details

This Backdoor does the following:

  • It generates its mutex using the registry keys it gathered from from HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 19.746.03
FIRST VSAPI PATTERN DATE: 29 Nov 2024
VSAPI OPR PATTERN File: 19.747.00
VSAPI OPR PATTERN Date: 30 Nov 2024

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

Scan your computer with your Trend Micro product to delete files detected as Backdoor.Win64.URSNIF.THIBGBD. 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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