alert smtp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET ADWARE_PUP Win32/RemoteUtilities Checkin via SMTP M2"; flow:established,to_server; content:"|0d 0a 0d 0a|UmVtb3RlIFV0aWxpdGllcy"; fast_pattern; pcre:"/(?:DQpTZXJ2ZXI6I|0KU2VydmVyOi|NClNlcnZlcjog)/R"; reference:md5,8574a1f23e4292f6d76857df1f70ff0e; classtype:pup-activity; sid:2034644; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_12_09, deployment Perimeter, performance_impact Low, confidence High, signature_severity Minor, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_01_12;)