alert http any any -> $HOME_NET any (msg:"ET WEB_SPECIFIC_APPS FreePBX Authentication Bypass via Forged Authorization Header (CVE-2025-66039)"; flow:established,to_server; http.uri; content:"/admin/"; startswith; content:"|2e|php|3f|"; http.header; content:"authorization|3a 20|basic ywrtaw46"; fast_pattern; nocase; http.method; content:"POST"; reference:url,horizon3.ai/attack-research/the-freepbx-rabbit-hole-cve-2025-66039-and-others/; reference:cve,2025-66039; classtype:web-application-attack; sid:2067120; rev:1; metadata:affected_product FreePBX, attack_target Server, tls_state TLSDecrypt, created_at 2026_01_27, cve CVE_2025_66039, deployment Perimeter, deployment Internal, deployment SSLDecrypt, signature_severity Major, tag Exploit, updated_at 2026_01_27, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application; target:dest_ip;)