Analysis by: Nathaniel Gregory Ragasa
 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • 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.

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

  TECHNICAL DETAILS

File Size: 1,927 bytes
File Type: PHP
Memory Resident: No
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 executes the following commands from a remote malicious user:

  • Execute Arbitrary Commands

Other Details

This Backdoor requires the existence of the following files to properly run:

  • {Malware Path}\wp-blog-header.php

It does the following:

  • It receives code passed through the POST request parameter 'a'
  • If it does not receive code passed through POST request parameter 'a':
    • It connects to the following URL: https://stick.{BLOCKED}inskydream.ga/analytics.js?s=07&b=345&cid=7457-85-2346788-24

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

It requires being hosted on a web server in order to proceed with its intended routine.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 18.106.04
FIRST VSAPI PATTERN DATE: 01 Dec 2022
VSAPI OPR PATTERN File: 18.107.00
VSAPI OPR PATTERN Date: 02 Dec 2022

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.PHP.WEBSHELL.SBJSRMUAB. 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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