Exploitation Activity of CVE-2025-59287 - WSUS Deserialization

Description

Detects cast exceptions in Windows Server Update Services (WSUS) application logs that highly indicate exploitation attempts of CVE-2025-59287, a deserialization vulnerability in WSUS.

Query · sigma

selection:
  Provider_Name: Windows Server Update Services
  EventID: 7053
  Data|contains|all:
  - System.InvalidCastException
  - System.Windows.Data.ObjectDataProvider
  - Unable to cast object of type
  - System.Windows.Media.Brush
condition: selection

Known false positives

  • Legitimate WSUS operations that may trigger similar error messages
Raw source Exploitation Activity of CVE-2025-59287 - WSUS Deserialization · Sigma
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Published by SigmaHQ/sigma ↗, licensed under Detection Rule License 1.1 ↗. Reproduced here unmodified. 
title: Exploitation Activity of CVE-2025-59287 - WSUS Deserialization
id: e5f66e87-7d6b-404f-92fe-7aa67814b5cd
status: experimental
description: |
    Detects cast exceptions in Windows Server Update Services (WSUS) application logs that highly indicate exploitation attempts of CVE-2025-59287, a deserialization vulnerability in WSUS.
references:
    - https://unit42.paloaltonetworks.com/cve-2025-59287/
    - https://hawktrace.com/blog/CVE-2025-59287-UNAUTH
    - https://github.com/0xBruno/WSUSploit.NET/tree/e239bce9d6b5f46a346e1e4c4d5e0a2a20d5c639
    - https://www.huntress.com/blog/exploitation-of-windows-server-update-services-remote-code-execution-vulnerability
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-10-31
tags:
    - attack.execution
    - attack.initial-access
    - attack.t1190
    - attack.t1203
    - cve.2025-59287
    - detection.emerging-threats
logsource:
    product: windows
    service: application
detection:
    selection:
        Provider_Name: 'Windows Server Update Services'
        EventID: 7053
        Data|contains|all:
           # Indicators of untrusted deserialization exploitation attempts
           # https://github.com/pwntester/ysoserial.net/issues/114
            - 'System.InvalidCastException'
            - 'System.Windows.Data.ObjectDataProvider'
            - 'Unable to cast object of type'
            - 'System.Windows.Media.Brush'
    condition: selection
falsepositives:
    - Legitimate WSUS operations that may trigger similar error messages
level: high

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