alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE MSIL/MosaiqueRAT CnC Checkin"; flow:established,to_server; dsize:<400; content:"|e1 00 00 00|"; startswith; content:"|00 00 00|Windows|20|"; fast_pattern; distance:0; content:"|00 00 00|Client|20|"; isdataat:!4,relative; reference:url,github.com/thdal/MosaiqueRAT; classtype:trojan-activity; sid:2032807; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_04_23, deployment Perimeter, malware_family MSIL_MosaiqueRAT, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_04_23;)