alert smtp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/Detplock Checkin via SMTP"; flow:established,to_server; content:"Subject|3a 20|Virus Infection Monitor|0d 0a|"; fast_pattern; content:"Content|2d|type|3a 20|multipart|2f|mixed|3b 20|boundary|3d 22 23|BOUNDARY|23 22 0d 0a|"; reference:md5,6ac14ccd294d75e340d48d19aa74be09; classtype:trojan-activity; sid:2031608; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_02_08, deployment Perimeter, malware_family Win32_Detplock, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_02_08;)