alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Link Implant CnC Activity (POST)"; flow:established,to_server; http.request_line; content:"POST /static/"; http.cookie; bsize:13; content:"banner=banner"; fast_pattern; http.header; strip_pseudo_headers; content:"x-request-id|3a 20|"; startswith; http.header_names; to_lowercase; content:!"|0d 0a|referer|0d 0a|"; reference:url,github.com/postrequest/link; classtype:command-and-control; sid:2037930; rev:3; metadata:attack_target Client_Endpoint, created_at 2022_08_04, deployment Perimeter, deployment SSLDecrypt, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_30;)