alert smtp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/DarkCloud Exfil Over SMTP (Agent)"; flow:established,to_server; content:"agent|3a 20|darkcloud|20|v"; fast_pattern; nocase; pcre:"/^\d+\x2e\d+/R"; classtype:trojan-activity; sid:2072020; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2026_09_14, deployment Perimeter, malware_family Win32_DarkCloud, confidence High, signature_severity Major, updated_at 2026_09_14;)