Analysis by: Clive Fuentebella
ALIASES:

Win32/Neshta.A virus (NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Virus

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This Virus 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: 611,840 bytes
File Type: EXE
Memory Resident: Yes
Payload: Drops files, Modifies files

Arrival Details

This Virus 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 Virus drops the following files:

  • %User Temp%\{Random characters}\{Malware file name}
  • %Windows%\svchost.com

Other System Modifications

This Virus modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
exefile\shell\open\
command
(Default) = %Windows%\svchost.com "%1" %*

Other Details

This Virus does the following:

  • It modifies files in the file system.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 17.160.02
FIRST VSAPI PATTERN DATE: 29 Oct 2021
VSAPI OPR PATTERN File: 17.161.00
VSAPI OPR PATTERN Date: 30 Oct 2021

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.Win32.TRX.XXPE50FFF049

Step 2

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 3

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 4

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\exefile\shell\open\command
    • From: (Default)=%Windows%\svchost.com "%1" %*
    • To: (Default)="%1" %*

Step 5

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %User Temp%\{Random characters}\{Malware file name}
  • %Windows%\svchost.com

Step 6

Scan your computer with your Trend Micro product to delete files detected as Virus.Win32.NESHTA.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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