Backdoor.Win64.SILVER.YXFAIZ

February 17, 2025
 Analysis by: Leidryn Saludez
 ALIASES:

Win64:MalwareX-gen [Trj] (AVAST)

 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.

  TECHNICAL DETAILS

File Size:

23,948,288 bytes

File Type:

EXE

Initial Samples Received Date:

22 Jan 2025

Payload:

Connects to URLs/IPs

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.

Backdoor Routine

This Backdoor connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://www.{BLOCKED}kzwerg.de/auth/auth/authenticate/samples.html
  • http://www.{BLOCKED}kzwerg.de/auth/auth/authenticate/samples.php

Other Details

This Backdoor does the following:

  • It spawns a new thread to decrypt "ccache.dat" and executes it to newly allocated memory.
  • It accepts and executes arbitrary commands from a remote server.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

19.854.03

FIRST VSAPI PATTERN DATE:

22 Jan 2025

VSAPI OPR PATTERN File:

19.855.00

VSAPI OPR PATTERN Date:

23 Jan 2025

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.XXPE50FFF089

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

Scan your computer with your Trend Micro product to delete files detected as Backdoor.Win64.SILVER.YXFAIZ. 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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