alert http any any -> $HOME_NET any (msg:"ET WEB_SPECIFIC_APPS D-Link Arbitrary File Read Via webproc errorpage Parameter (CVE-2021-27250)"; flow:established,to_server; http.method; content:"POST"; http.uri; bsize:16; content:"/cgi-bin/webproc"; fast_pattern; http.cookie; content:"sys_UserName|3d|admin"; http.request_body; content:"errorpage|3d|"; pcre:"/^(?:\x2f|[^\x26]*?(?:(?:\x2e|%2[Ee]){1,2}(?:\x2f|\x5c|%5[Cc]|%2[Ff]){1,}){2,})/R"; reference:cve,2021-27250; reference:url,github.com/PeiQi0/PeiQi-WIKI-Book/tree/main/docs/wiki/iot; classtype:attempted-admin; sid:2063272; rev:1; metadata:affected_product D_Link, attack_target Networking_Equipment, tls_state plaintext, created_at 2025_07_02, cve CVE_2021_27250, deployment Perimeter, deployment Internal, performance_impact Low, confidence High, signature_severity Major, tag Exploit, updated_at 2025_07_02, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application; target:dest_ip;)