Rootkit.Linux.WINNTI.A

October 25, 2022
 Analysis by: Jeffrey Francis Bonaobra
 ALIASES:

Rootkit.Linux.Processhider.d (KASPERSKY)

 PLATFORM:

Linux

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

  • Threat Type: Rootkit

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

This Rootkit 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:

24,512 bytes

File Type:

ELF

Memory Resident:

No

Initial Samples Received Date:

20 Oct 2022

Arrival Details

This Rootkit arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Other Details

This Rootkit does the following:

  • It is used by Backdoor.Linux.WINNTI.F for its rootkit capabilities.
  • It checks if the environment variable HIDE_THIS_SHELL is set.
  • It hooks the following functions of the current process to hide the malware's operations:
    • __lxstat64
    • __xstat
    • __xstat64
    • access
    • fopen
    • fopen64
    • link
    • lstat64
    • open
    • open64
    • opendir
    • readdir
    • readdir64
    • rmdir
    • stat
    • stat64
    • unlink
    • unlinkat
    • x_lxstat
    • xlstat

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

17.896.03

FIRST VSAPI PATTERN DATE:

25 Oct 2022

VSAPI OPR PATTERN File:

17.897.00

VSAPI OPR PATTERN Date:

26 Oct 2022

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.ELF.TRX.XXELFC1DFF020

Step 2

Scan your computer with your Trend Micro product to delete files detected as Rootkit.Linux.WINNTI.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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