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; to_lowercase; 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;)