alert http any any -> $HOME_NET any (msg:"ET WEB_SPECIFIC_APPS TBK DVR-4104/4216 Command Injection Attempt (CVE-2024-3721)"; flow:established,to_server; http.uri; content:"/device.rsp|3f|opt|3d|sys|26|cmd|3d 5f 5f 5f|S|5f|O|5f|S|5f|T|5f|R|5f|E|5f|A|5f|MAX|5f 5f 5f|"; startswith; fast_pattern; content:"mdb|3d|"; within:20; content:"mdc|3d|"; within:20; pcre:"/^[^\x26]*?(?:(?:\x3b|%3[Bb])|(?:\x0a|%0[Aa])|(?:\x60|%60)|(?:\x7c|%7[Cc])|(?:\x24|%24))+/R"; reference:cve,2024-3721; reference:url,github.com/netsecfish/tbk_dvr_command_injection; classtype:attempted-admin; sid:2061111; rev:1; metadata:affected_product DVR, attack_target IoT, tls_state plaintext, created_at 2025_03_26, cve CVE_2024_3721, deployment Perimeter, deployment Internal, performance_impact Low, confidence High, signature_severity Major, tag Exploit, updated_at 2025_03_26, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application; target:dest_ip;)