Backdoor.PHP.WEBSHELL.SBJKSA

August 30, 2022
 Analysis by: Paul Steven Nadera
 Modified by: Eleazar Valles
 ALIASES:

Backdoor.PHP.WebShell.tk (KASPERSKY)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • 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:

15,008 bytes

File Type:

PHP

Memory Resident:

No

Initial Samples Received Date:

23 Jan 2020

Payload:

Collects system information, Terminates processes, Downloads files, Modifies files, Executes files, Deletes files

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 PHP Code
  • Extract Zip Files
  • Upload/Download Files
  • Manage Files (Change Access Permissions, Delete, Rename, and Modify Files)
  • Read File in plaintext and Base64 Format
  • Create Files and Directories
  • Delete Itself

Information Theft

This Backdoor gathers the following data:

  • Computer Name
  • User Name
  • OS Description
  • PHP Information

Other Details

This Backdoor 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:

15.638.08

FIRST VSAPI PATTERN DATE:

23 Jan 2020

VSAPI OPR PATTERN File:

15.639.00

VSAPI OPR PATTERN Date:

24 Jan 2020

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.SBJKSA. 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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