Backdoor.ASP.WEBSHELL.X

June 04, 2024
 Analysis by: Raymart Christian Yambot
 ALIASES:

Backdoor.Asp.Webshell.K (BITDEFENDER)

 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.

  TECHNICAL DETAILS

File Size:

47,360 bytes

File Type:

ASP

Memory Resident:

No

Initial Samples Received Date:

22 May 2024

Payload:

Collects system information, Connects to URLs/IPs, Executes commands, Steals information

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
  • Execute SQL commands
  • Browse files and directories on the web server.
  • Upload files to the server.
  • Download files from the server.
  • Create new files and directories.
  • Edit existing files.
  • Delete files and directories.
  • Change file attributes (read-only, hidden, system, archive).

Information Theft

This Backdoor gathers the following data:

  • Server IP address
  • Machine name
  • Network name
  • Running user's name
  • Operating system version
  • Server uptime and current time
  • IIS (web server) version
  • HTTPS status
  • Request paths
  • Server port
  • Session ID

Other Details

This Backdoor does the following:

  • It receives arbitrary commands passed through its request parameter.
  • It requires login credential to access its functionalities.
  • It navigates to the specified website when the 'lake' hyperlink is clicked.
    • http://{BLOCKED}2.0x54.org

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

19.374.04

FIRST VSAPI PATTERN DATE:

31 May 2024

VSAPI OPR PATTERN File:

19.375.00

VSAPI OPR PATTERN Date:

01 Jun 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.ASP.WEBSHELL.X. 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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