Backdoor.Win32.ZARDOOR.A


 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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 may be dropped by other malware.

It executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size:

1,729,024 bytes

File Type:

DLL

Memory Resident:

No

Initial Samples Received Date:

01 Mar 2024

Payload:

Connects to URLs/IPs, Collects system 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.

It may be dropped by the following malware:

Installation

This Backdoor adds the following processes:

  • cmd /c wmic csproduct get indentifyingnumber

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

  • 3e603a07-7b2d-4a15-afef-7e9a0841e4d5
  • ThreadMutex12453
  • rrx_{4 digit number}
  • mutex_pro

Backdoor Routine

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

  • Encrypt and send data to its C2 server
  • Execute remotely fetched PE payload
  • Search for session ID
  • Plugin exit
  • Remote shellcode execution
  • Delete itself
  • Update C2 IP()IP/domain_name:port)
  • Do nothing

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

  • {BLOCKED}.{BLOCKED}.{BLOCKED}.1/index.html
  • {BLOCKED}.{BLOCKED}.{BLOCKED}.2/index.html
  • {BLOCKED}.{BLOCKED}.{BLOCKED}.3/index.html

Information Theft

This Backdoor gathers the following data:

  • Windows Version
  • Operating System
  • Hostname
  • Computer name
  • Username
  • SID number

Other Details

This Backdoor does the following:

  • It needs a program that allows network applications to operate through a SOCKS or HTTPS proxy to establish its connection to its C2

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

19.202.05

FIRST VSAPI PATTERN DATE:

07 Mar 2024

VSAPI OPR PATTERN File:

19.203.00

VSAPI OPR PATTERN Date:

08 Mar 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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Scan your computer with your Trend Micro product to delete files detected as Backdoor.Win32.ZARDOOR.A. 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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