Analysis by: Ricardo III Valdez
ALIASES:

REG/Disabler.NAD trojan (NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan 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: 187 bytes
File Type: REG
Memory Resident: Yes
Initial Samples Received Date: 03 Apr 2023

Arrival Details

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

Installation

This Trojan adds the following processes:

  • "regedit.exe" "{Malware File Path}\{Malware File Name}.reg"

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender
DisableAntiSpyware = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender
DisableRoutinelyTaking Action = 1

(Note: The default value data of the said registry entry is 0.)

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 18.362.05
FIRST VSAPI PATTERN DATE: 04 Apr 2023
VSAPI OPR PATTERN File: 18.363.00
VSAPI OPR PATTERN Date: 05 Apr 2023

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

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender
    • DisableAntiSpyware = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender
    • DisableRoutinelyTaking Action = 1

Step 3

Scan your computer with your Trend Micro product to delete files detected as Trojan.Win32.KILLWINDEF.AA. 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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