alert http any any -> $HOME_NET any (msg:"ET WEB_SPECIFIC_APPS FreePBX Recordings.class.php file Parameter Command Injection Attempt (CVE-2026-28287)"; flow:established,to_server; http.method; content:"POST"; http.uri; bsize:15; content:"/admin/ajax.php"; http.request_body; content:"file|3d|"; pcre:"/^[^\x26]*?(?:(?:\x3b|%3[Bb])|(?:\x0a|%0[Aa])|(?:\x60|%60)|(?:\x7c|%7[Cc])|(?:\x24|%24))+/R"; content:"command|3d|"; pcre:"/^(?:convert|gethtml5)/R"; content:"module|3d|recordings"; fast_pattern; reference:url,attackerkb.com/topics/i5qGi63oCf/cve-2026-28287; reference:cve,2026-28287; classtype:attempted-admin; sid:2068314; rev:1; metadata:attack_target Networking_Equipment, tls_state plaintext, created_at 2026_03_17, cve CVE_2026_28287, deployment Perimeter, deployment Internal, performance_impact Low, confidence High, signature_severity Major, tag Exploit, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2026_03_17, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application; target:dest_ip;)