Worm.AutoIt.STARTER.CC

August 31, 2023
 Analysis by: John Rainier Navato
 ALIASES:

Win32/Packed.Autoit.H (NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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

It requires being executed with a specific argument/parameter, an additional component, or in a specific environment in order to proceed with its intended routine.

  TECHNICAL DETAILS

File Size:

234,668 bytes

File Type:

AU3

Initial Samples Received Date:

29 Jul 2021

Payload:

Creates files, Drops files, Copies files

Arrival Details

This Worm 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 Worm drops the following copies of itself into the affected system:

  • %System Root%\MicrosoftSecurity\{Current Malware File Name}.a3x

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It drops the following files:

  • %User Temp%\aut{4 Random Alphanumeric characters}.tmp
  • %User Temp%\{7 Random characters}

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • "%System%\cmd.exe" /c start %System Root%\MicrosoftSecurity/MicrosoftSecurity.exe %System Root%\MicrosoftSecurity/Microsoft.a3x

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It creates the following folders:

  • %System Root%\MicrosoftSecurity

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

Other Details

This Worm does the following:

  • It copies all files from the current malware file path to %System Root%\MicrosoftSecurity.

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It requires being executed with a specific argument/parameter, an additional component, or in a specific environment in order to proceed with its intended routine.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

16.872.08

FIRST VSAPI PATTERN DATE:

29 Jul 2021

VSAPI OPR PATTERN File:

16.873.00

VSAPI OPR PATTERN Date:

30 Jul 2021

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

Search and delete these files

[ 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%\aut{4 Random Alphanumeric characters}.tmp
  • %User Temp%\{7 Random characters}
  • %System Root%\MicrosoftSecurity\{Current Malware File Name}.a3x
  • %System Root%\MicrosoftSecurity\{All Copied Files from Current Malware File Path}

Step 4

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %System Root%\MicrosoftSecurity

Step 5

Scan your computer with your Trend Micro product to delete files detected as Worm.AutoIt.STARTER.CC. 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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