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Worm.Win32.PALEVO.AL

January 29, 2024
 ALIASES:

P2P-Worm.Win32.Palevo (IKARUS)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • 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 drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

37,888 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

09 Jan 2024

Payload:

Connects to URLs/IPs, Drops 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%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe → with READONLY, HIDDEN, and SYSTEM attributes

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

It drops the following files:

  • %System Root%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\Desktop.ini → with HIDDEN, and SYSTEM attributes
  • {Removable Drive Letter}:\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\Desktop.ini → with HIDDEN, and SYSTEM attributes
  • {Removable Drive Letter}:\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\autorun.inf → with READONLY, HIDDEN, and SYSTEM attributes

(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%\RECYCLER → with READONLY, HIDDEN, and SYSTEM attributes
  • %System Root%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013 → with READONLY, HIDDEN, and SYSTEM attributes

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

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • asd-6+094997_

It injects threads into the following normal process(es):

  • explorer.exe

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
Internet Security Service = %System Root%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe → if HKEY_LOCAL_MACHINE\Software\Microsoft\Active Setup\Installed Components\{28ABC5C0-4FCB-11CF-AAX5-81CX1C635612}\StubPath does not exist

HKEY_LOCAL_MACHINE\Software\Microsoft\
Active Setup\Installed Components\{28ABC5C0-4FCB-11CF-AAX5-81CX1C635612}
StubPath = %System Root%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe

Other System Modifications

This Worm adds the following registry keys as part of its installation routine:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Active Setup\Installed Components
{28ABC5C0-4FCB-11CF-AAX5-81CX1C635612} =

Propagation

This Worm creates the following folders in all removable drives:

  • {Removable Drive Letter}:\RECYCLER → with READONLY, HIDDEN, and SYSTEM attributes
  • {Removable Drive Letter}:\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013 → with READONLY, HIDDEN, and SYSTEM attributes

It drops the following copy(ies) of itself in all removable drives:

  • {Removable Drive Letter}:\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe → with READONLY, HIDDEN, and SYSTEM attributes

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

[autorun]
open=RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open=Open
shell\open\command=RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe
shell\open\default=1

Backdoor Routine

This Worm executes the following commands from a remote malicious user:

  • Flooding (DDOS)
  • Execute arbitrary commands from remote user

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • tcp://{BLOCKED}adool400.com:6666

However, as of this writing, the said sites are inaccessible.

Rootkit Capabilities

This Worm does not have rootkit capabilities.

NOTES:

This Worm does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

18.930.03

FIRST VSAPI PATTERN DATE:

09 Jan 2024

VSAPI OPR PATTERN File:

18.931.00

VSAPI OPR PATTERN Date:

10 Jan 2024

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.XXPE50FFF076

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_LOCAL_MACHINE\Software\Microsoft\Active Setup\Installed Components\{28ABC5C0-4FCB-11CF-AAX5-81CX1C635612}
    • StubPath = %System Root%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Internet Security Service = %System Root%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Active Setup\Installed Components
    • {28ABC5C0-4FCB-11CF-AAX5-81CX1C635612}

Step 7

Search and delete AUTORUN.INF files created by Worm.Win32.PALEVO.AL that contain these strings

[ Learn More ]
 
  • [autorun]
  • open=RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe
  • icon=%SystemRoot%\system32\SHELL32.dll,4
  • action=Open folder to view files
  • shell\open=Open
  • shell\open\command=RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe
  • shell\open\default=1

Step 8

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.
  • %System Root%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\Desktop.ini
  • %System Root%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe
  • {Removable Drive Letter}:\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\Desktop.ini
  • {Removable Drive Letter}:\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013\ise32.exe

Step 9

Search and delete these folders

[ 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%\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013
  • %System Root%\RECYCLER
  • {Removable Drive Letter}:\RECYCLER\S-1-5-21-1482476501-1644491937-682003330-1013
  • {Removable Drive Letter}:\RECYCLER

Step 10

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Worm.Win32.PALEVO.AL. 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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