CVE-2025-59287 — Microsoft WSUS Remote Code Execution

Key facts

CVE-2025-59287 is a Critical (9.8) vulnerability: Microsoft WSUS Remote Code Execution. This entry ships ready-to-deploy detection and prevention rules (Snort, YARA, Nginx, Apache) plus a detection-only PoC and a Docker test lab. It is on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2025-10-24), confirming active exploitation in the wild.

Actively exploited — on the CISA KEV catalog

CVE-2025-59287 is listed on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2025-10-24), confirming exploitation in the wild. Federal remediation deadline: 2025-11-14. Prioritise patching and deploy the detection and prevention rules below.

CVE	CVE-2025-59287
Severity	Critical (9.8)
CISA KEV	Actively exploited (added 2025-10-24)
Detection / prevention	Snort, YARA, Nginx, Apache
PoC	poc.py
Source	2025/CVE-2025-59287/

Details

CVE-2025-59287 is a Critical (9.8) vulnerability: Microsoft WSUS Remote Code Execution. This entry ships a detection-only proof-of-concept (PoC), a Docker test lab, and ready-to-deploy detection and prevention rules (Snort, YARA, Nginx, Apache) — see Detection and prevention below. Source: NVD record.

Overview

Attribute	Value
CVE ID	CVE-2025-59287
Severity	Critical
CVSS Score	9.8
Affected Product	Windows Server Update Services (WSUS)
Vulnerability Type	Unauthenticated RCE
Exploitation Status	Actively Exploited

Description

CVE-2025-59287 is a critical unauthenticated remote code execution vulnerability in Microsoft's Windows Server Update Services (WSUS). The vulnerability allows remote attackers to execute arbitrary code on WSUS servers without authentication.

Affected Versions

• Windows Server 2016
• Windows Server 2019
• Windows Server 2022

Technical Details

Root Cause

The vulnerability exists in how WSUS processes certain specially crafted HTTP requests. An attacker can send malicious requests that bypass authentication and trigger code execution in the context of the WSUS service.

Attack Vector

1. Attacker identifies WSUS server (typically on port 8530/8531)
2. Sends specially crafted HTTP request
3. Server processes request without proper authentication
4. Arbitrary code executes with SYSTEM privileges

Impact

• Complete compromise of WSUS infrastructure
• Potential for supply chain attacks via malicious updates
• Lateral movement across enterprise networks
• Access to all managed Windows endpoints

Mitigation

1. Apply Microsoft emergency out-of-band patch (October 23, 2025)
2. Restrict network access to WSUS ports
3. Monitor for suspicious WSUS traffic
4. Implement network segmentation

Verification Process

The PoC uses a multi-stage verification approach:

Step 1: Product/Version Detection (Passive)

[*] Query target endpoint
[*] Detect product signatures and extract version
[*] Check if version is in vulnerable range

Step 2: Active Vulnerability Testing

Method	Description	Detection
Error-based	Tests for error messages indicating vulnerability	Error indicators in response
Timing-based	Measures response delay with payload	Response time significantly longer
Response-based	Checks for expected patterns in response	Vulnerability indicators present

Verification Flow

┌─────────────────────────────────────────────────────────────┐
│                    Product Detection                         │
│  Query target → Detect product/version                      │
│  Check if version in vulnerable range                       │
└─────────────────────────────────────────────────────────────┘
                              ↓
┌─────────────────────────────────────────────────────────────┐
│               Active Vulnerability Testing                   │
│                                                              │
│  1. Error-based Test                                         │
│     └─ Send payload → Check for error indicators            │
│     └─ If error found → CONFIRMED VULNERABLE                │
│                                                              │
│  2. Timing-based Test                                        │
│     └─ Send delay payload → Measure response time           │
│     └─ If delayed → CONFIRMED VULNERABLE                    │
│                                                              │
│  3. Response-based Test                                      │
│     └─ Send payload → Check response content                │
│     └─ If pattern matches → CONFIRMED VULNERABLE            │
└─────────────────────────────────────────────────────────────┘

Usage

# Full vulnerability check (version + active testing)
python3 poc.py -t https://target.com -c

# Version-only check (passive, no payloads sent)
python3 poc.py -t https://target.com -c --version-only

References

• Microsoft Security Advisory
• Unit42 Analysis

Detection and prevention

Ready-to-deploy defensive rules for CVE-2025-59287, for authorized testing and blue-team detection engineering:

• Snort IDS signature — prevention/snort.rules
• YARA detection rule — prevention/yara.yar
• Nginx mitigation — prevention/nginx.conf
• Apache HTTPD mitigation — prevention/httpd.conf
• Detection-only PoC — poc.py
• Rule notes — prevention/README.md

References: NVD — CVE-2025-59287 · full write-up on the searchable site

Detection & prevention rules

Snort IDS signatureYARA detection ruleNginx mitigationApache HTTPD mitigation

# CVE-2025-59287 - Snort IDS Rules
# Severity: High

# Detect potential exploit attempts
alert tcp $EXTERNAL_NET any -> $HOME_NET $HTTP_PORTS (
    msg:"CVE-2025-59287 Potential Exploit Attempt";
    flow:to_server,established;
    content:".."; http_uri;
    classtype:web-application-attack;
    sid:2025592871;
    rev:1;
    metadata:cve CVE-2025-59287, severity high;
)

# Detect suspicious patterns in request
alert tcp $EXTERNAL_NET any -> $HOME_NET $HTTP_PORTS (
    msg:"CVE-2025-59287 Suspicious Request Pattern";
    flow:to_server,established;
    pcre:"/(%2e%2e|%252e|\x00)/Ui";
    classtype:web-application-attack;
    sid:2025592872;
    rev:1;
    metadata:cve CVE-2025-59287, severity high;
)

:material-file-download: prevention/snort.rules

/*
 * CVE-2025-59287 - YARA Detection Rules
 */

rule CVE_2025_59287_Exploit {
    meta:
        description = "Detects potential CVE-2025-59287 exploit attempts"
        author = "Security Research Team"
        severity = "high"
        cve = "CVE-2025-59287"

    strings:
        $path_traversal1 = "../" ascii wide
        $path_traversal2 = "..\" ascii wide
        $encoded1 = "%2e%2e" ascii wide nocase
        $encoded2 = "%252e" ascii wide nocase
        $null_byte = "%00" ascii wide

    condition:
        any of them
}

:material-file-download: prevention/yara.yar

# CVE-2025-59287 - Prevention Rules for Nginx

# Block common exploit patterns
location / {
    # Rate limiting
    limit_req zone=general burst=20 nodelay;

    # Block suspicious patterns
    if ($request_uri ~* "(\.\.[\/]|%2e%2e|%252e)") {
        return 403;
    }

    # Security headers
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-Frame-Options "DENY" always;
    add_header X-XSS-Protection "1; mode=block" always;
}

# Log suspicious activity
access_log /var/log/nginx/CVE-2025-59287-access.log;
error_log /var/log/nginx/CVE-2025-59287-error.log;

:material-file-download: prevention/nginx.conf

# CVE-2025-59287 - Prevention Rules for Apache httpd

# Block common exploit patterns
<IfModule mod_rewrite.c>
    RewriteEngine On

    # Block path traversal
    RewriteCond %{REQUEST_URI} (\.\.[\/]|%2e%2e|%252e) [NC]
    RewriteRule .* - [F,L]

    # Block null bytes
    RewriteCond %{REQUEST_URI} %00 [NC]
    RewriteRule .* - [F,L]
</IfModule>

# Security headers
Header always set X-Content-Type-Options "nosniff"
Header always set X-Frame-Options "DENY"
Header always set X-XSS-Protection "1; mode=block"

# Enable logging
CustomLog /var/log/httpd/CVE-2025-59287-access.log combined
ErrorLog /var/log/httpd/CVE-2025-59287-error.log

:material-file-download: prevention/httpd.conf

Frequently asked questions

What is CVE-2025-59287?

CVE-2025-59287 is a Critical (9.8) vulnerability: Microsoft WSUS Remote Code Execution. This entry ships ready-to-deploy detection and prevention rules (Snort, YARA, Nginx, Apache) plus a detection-only PoC and a Docker test lab. It is on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2025-10-24), confirming active exploitation in the wild.

How do I detect CVE-2025-59287?

Deploy the Snort and YARA detection rule included with this entry (see Detection & prevention rules below), then validate it against the detection-only PoC in the Docker test lab.

How do I block or mitigate CVE-2025-59287?

Apply the Nginx and Apache mitigation config included with this entry, and upgrade to a fixed version per the vendor advisory (see the NVD record for affected versions).

Is CVE-2025-59287 actively exploited?

Yes. CVE-2025-59287 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, added 2025-10-24, which means it has been exploited in the wild. CISA set a federal remediation deadline of 2025-11-14. Prioritise patching and deploy the detection and prevention rules above.

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For authorized security testing and research only. See the full source and NVD record.