alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Magecart/Skimmer - _try_action Exfil Attempt"; flow:established,to_server; http.method; content:"POST"; http.uri; content:".png"; endswith; http.content_type; content:"application/x-www-form-urlencoded"; startswith; http.request_body; content:"cid="; startswith; fast_pattern; content:"&host="; reference:url,lukeleal.com/research/posts/cdn-frontend-skimmer/; classtype:trojan-activity; sid:2032788; rev:1; metadata:affected_product Web_Browsers, attack_target Client_Endpoint, created_at 2021_04_20, deployment Perimeter, deployment SSLDecrypt, confidence High, signature_severity Major, tag CardSkimmer, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_04_20;)