alert smtp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Atom Logger exfil via SMTP"; flow:established,to_server; content:"Subject|3a 20|["; content:"|20 7c 20|Atom Logger"; within:100; fast_pattern; reference:md5,78bd897a638e7c0d3c00c31c8c68f18b; classtype:trojan-activity; sid:2026825; rev:5; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_01_17, deployment Perimeter, malware_family AtomLogger, performance_impact Moderate, confidence High, signature_severity Critical, updated_at 2023_05_30;)