alert smtp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE MSIL/Kryptik.XSY Data Exfil via SMTP"; flow:established,to_server; content:"|0d 0a|Subject: PW_"; content:"filename|3d 22|PW_"; content:"_"; distance:0; content:"_"; distance:4; within:1; content:"_"; distance:2; within:1; content:"_"; distance:2; within:1; content:"_"; distance:2; within:1; content:"_"; distance:2; within:1; content:".html|22 0d 0a 0d 0a|VGltZTog"; distance:2; within:18; fast_pattern; reference:md5,61181c9665789225439d04d6eef5527f; classtype:command-and-control; sid:2030887; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_09_17, deployment Perimeter, malware_family MSIL_Kryptik_XSY, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_17;)