alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Possible Zeus GameOver Connectivity Check 2"; flow:established,to_server; urilen:1; http.host; content:"windowsupdate.microsoft.com"; bsize:27; http.connection; content:"Close"; fast_pattern; startswith; http.header_names; content:!"Accept|0d 0a|"; content:!"Referer|0d 0a|"; reference:md5,236bde81355e075e7ed6bcdc60daefcb; classtype:trojan-activity; sid:2019155; rev:5; metadata:created_at 2014_09_10, deprecation_reason Performance, performance_impact Significant, confidence Medium, signature_severity Major, updated_at 2024_04_29;)