alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE SiameseKitten/Lyceum/Hexane MSIL/Shark Uploading to CnC"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"?q="; content:"o543n"; endswith; fast_pattern; http.user_agent; content:"|28|Windows|20|NT|20|10.0|3b 20|Win64|3b 20|x64|29|"; http.request_body; content:"|7b 22|Data|22 3a 5b 22|"; startswith; pcre:"/^(?:[A-Z0-9+/]{4})*(?:[A-Z0-9+/]{2}==|[A-Z0-9+/]{3}=|[A-Z0-9+/]{4})/R"; content:"|22 5d 7d|"; classtype:command-and-control; sid:2033762; rev:1; metadata:created_at 2021_08_22, malware_family Shark, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_08_22;)