alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Shellshock Worm Checkin"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/.c.php?request="; fast_pattern; http.header_names; content:!"Referer|0d 0a|"; reference:url,volexity.com/blog/?p=118; classtype:command-and-control; sid:2020887; rev:4; metadata:created_at 2015_04_09, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_30;)