ET WEB_SPECIFIC_APPS Fortinet Authentication Bypass via Node.js Websocket (CVE-2024-55591)

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET WEB_SPECIFIC_APPS Fortinet Authentication Bypass via Node.js Websocket (CVE-2024-55591)";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:"/";
    pcre:"/^\w+\-[a-zA-Z0-9]{6}/R";
    http.header;
    content:"Sec-WebSocket-Key|3a 20|"; fast_pattern;
    content:"Upgrade|3a 20|websocket";
    content:!"Origin|3a 20|http";
    reference:url,github.com/watchtowrlabs/fortios-auth-bypass-check-CVE-2024-55591;
    reference:cve,2024-55591;
    classtype:web-application-attack;
    sid:2059283; rev:1;
    metadata:affected_product Fortigate, attack_target Server, tls_state TLSDecrypt, created_at 2025_01_16, cve CVE_2024_55591, deployment Perimeter, deployment Internal, deployment SSLDecrypt, confidence High, signature_severity Major, tag Exploit, tag CISA_KEV, updated_at 2025_01_16, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application;
    target:dest_ip;
)