ET WEB_SERVER Cisco ASA/FTD WebVPN Authentication Bypass (CVE-2025-20362)

alert http any any -> $HOME_NET any (
    msg:"ET WEB_SERVER Cisco ASA/FTD WebVPN Authentication Bypass (CVE-2025-20362)";
    flow:established,to_server;
    http.uri.raw;
    content:"/+CSCOU+";
    pcre:"/^(?:\x2e|%2[Ee]|\x2f|\x5c|%5[Cc]|%2[Ff]){2,}/R";
    content:"+CSCOE+/"; fast_pattern; distance:0;
    reference:url,attackerkb.com/topics/Szq5u0xgUX/cve-2025-20362/rapid7-analysis;
    reference:cve,2025-20362;
    classtype:web-application-attack;
    sid:2065051; rev:1;
    metadata:affected_product Cisco_ASA, affected_product Cisco_FTD, attack_target Server, tls_state TLSDecrypt, created_at 2025_10_06, cve CVE_2025_20362, deployment Perimeter, deployment Internal, deployment SSLDecrypt, confidence High, signature_severity Major, tag Exploit, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_10_06, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application;
    target:dest_ip;
)