alert tcp $EXTERNAL_NET any -> $SMTP_SERVERS 25 (msg:"ET MALWARE DHL Spam Inbound"; flow:established,to_server; content:"Content-Disposition|3A| attachment|3b|"; content:"|22|filename=dhl_"; nocase; content:".zip|22|"; nocase; classtype:trojan-activity; sid:2012493; rev:3; metadata:created_at 2011_03_12, signature_severity Major, updated_at 2019_07_26;)