alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE cryptodefense Checkin"; flow:established,to_server; http.method; content:"POST"; http.content_type; content:"multipart/form-data|3b 20|boundary="; startswith; http.request_body; content:"filename="; fast_pattern; content:"form-data|3b 20|name="; pcre:"/^[\x2d]+(?P<boundry>[0-9]+)\r\n.+form-data\x3b\x20name\x3d[\x22\27][a-z][\x22\27]\x3b\x20filename\x3d[\x22\x27](?P=boundry)[\x22\x27]/si"; http.header_names; content:!"|0d 0a|Referer|0d 0a|"; content:!"|0d 0a|Accept-Encoding|0d 0a|"; classtype:command-and-control; sid:2018386; rev:4; metadata:created_at 2014_04_14, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_03_01;)