alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE W32/Emotet CnC Beacon 3"; flow:established,to_server; http.method; content:"GET"; http.uri; content:!"."; content:!"&"; content:!"-"; http.header_names; content:"|0d 0a|Cookie|0d 0a|Host|0d 0a|Connection|0d 0a|Cache-Control|0d 0a 0d 0a|"; fast_pattern; http.header; content:"|0d 0a|Connection|3a 20|Keep-Alive|0d 0a|Cache-Control|3a 20|no-cache|0d 0a|"; endswith; http.host; pcre:"/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/"; http.cookie; bsize:>250; pcre:"/^[A-Za-z0-9]{1,15}=(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=|[A-Za-z0-9+\/]{4})$/i"; reference:md5,bc3532085a0b4febd9eed51aac2180d0; classtype:command-and-control; sid:2034459; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_11_15, deployment Perimeter, malware_family Emotet, performance_impact Moderate, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_11_15;)