alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET DELETED Possible Spambot getting new exe url"; flow:established,to_server; content:"404.txt"; nocase; http_uri; content:"404"; content:!"User-Agent|3a|"; nocase; http_header; classtype:trojan-activity; sid:2002989; rev:8; metadata:created_at 2010_07_30, signature_severity Unknown, updated_at 2019_07_26;)