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Worm.MSIL.BLADABINDI.AI

July 07, 2022
 Analysis by: Eleazar Valles
 ALIASES:

HEUR:Trojan.Win32.Generic (KASPERSKY)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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.

  TECHNICAL DETAILS

File Size:

276,992 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

25 Feb 2022

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:

  • %User Temp%\explorel.exe
  • {Removable Drive}\38bab302a311b237fe2b5c7b2b522c8c.exe

(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 drops the following files:

  • {Malware Path}\.tmp

It adds the following processes:

  • %User Temp%\explorel.exe
  • netsh firewall add allowedprogram "%User Temp%\explorel.exe" "explorel.exe" ENABLE

(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).)

Autostart Technique

This Worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
38bab302a311b237fe2b5c7b2b522c8c = "%User Temp%\explorel.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
38bab302a311b237fe2b5c7b2b522c8c = "%User Temp%\explorel.exe"

It drops the following file(s) in the Startup Items folder to enable its automatic execution at every system startup:

  • %User Startup%\38bab302a311b237fe2b5c7b2b522c8c.exe

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).)

Other Details

This Worm adds the following registry keys:

HKEY_CURRENT_USER\Software\38bab302a311b237fe2b5c7b2b522c8c

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\MediaResources

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\MediaResources\msvideo

It does the following:

  • It changes the file attributes of the dropped copy of itself in removable drives to Hidden

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

17.672.01

FIRST VSAPI PATTERN DATE:

06 Jul 2022

VSAPI OPR PATTERN File:

17.673.00

VSAPI OPR PATTERN Date:

07 Jul 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.Win32.TRX.XXPE50FFF053

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

Restart in Safe Mode

[ Learn More ]

Step 5

Delete this 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • 38bab302a311b237fe2b5c7b2b522c8c = "%User Temp%\explorel.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • 38bab302a311b237fe2b5c7b2b522c8c = "%User Temp%\explorel.exe"

Step 6

Delete this registry key

[ 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_CURRENT_USER\Software\
    • 38bab302a311b237fe2b5c7b2b522c8c
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\
    • MediaResources
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\MediaResources\
    • msvideo

Step 7

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%\explorel.exe
  • {Removable Drive}\38bab302a311b237fe2b5c7b2b522c8c.exe
  • %User Startup%\38bab302a311b237fe2b5c7b2b522c8c.exe
  • {Malware Path and Name}\.tmp

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Worm.MSIL.BLADABINDI.AI. 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 this Knowledge Base page for more information.


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