alert tcp ![66.220.157.64/26,66.220.157.16/29,66.220.157.48/28,66.220.157.24/29,66.220.144.128/27,66.220.157.128/27,66.220.144.160/29,66.220.157.160/29,66.220.144.168/29,66.220.157.168/29] any -> $SMTP_SERVERS 25 (msg:"ET DELETED Facebook Spam Inbound (1)"; flow:established,to_server; content:"facebook.com"; nocase; content:"Content-Disposition|3A| attachment|3b|"; nocase; content:"filename"; content:"Facebook_"; within:50; pcre:"/filename=.*facebook.*\.(rar|exe|zip)/i"; reference:url,postmaster.facebook.com/outbound; classtype:trojan-activity; sid:2010497; rev:10; metadata:created_at 2010_07_30, signature_severity Unknown, updated_at 2019_07_26;)