alert http any 53 -> [$HOME_NET,$HTTP_SERVERS,$DNS_SERVERS] any (msg:"ET INFO Suspicious HTTP POST Request on Port 53 Inbound"; flow:established,to_server; http.method; content:"POST"; http.request_line; content:"POST|20|"; startswith; content:"|20|HTTP|2f|"; within:50; fast_pattern; classtype:bad-unknown; sid:2030523; rev:4; metadata:affected_product Windows_DNS_server, created_at 2020_07_15, performance_impact Significant, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_03_27;)