alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Backdoor.Egobot Checkin"; flow:to_server,established; http.uri; content:".php?arg1="; nocase; fast_pattern; content:"&arg2="; pcre:"/&arg2=((?:[a-f0-9]{32})|(?:[A-Za-z0-9\x2b\x2f]{4})*(?:[A-Za-z0-9\x2b\x2f]{2}==|[A-Za-z0-9\x2b\x2f]{3}=|[A-Za-z0-9\x2b\x2f]{4}))(?:&|$)/i"; reference:url,symantec.com/connect/blogs/backdooregobot-how-effectively-execute-targeted-campaign; classtype:command-and-control; sid:2017600; rev:4; metadata:created_at 2013_10_15, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_21;)