alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed FinSpy Domain (browserupdate .download in TLS SNI)"; flow:established,to_server; tls.sni; dotprefix; content:".browserupdate.download"; endswith; fast_pattern; reference:url,www.amnesty.org/en/latest/research/2020/09/german-made-finspy-spyware-found-in-egypt-and-mac-and-linux-versions-revealed/; reference:url,github.com/AmnestyTech/investigations/blob/master/2020-09-25_finfisher/domains.txt; classtype:domain-c2; sid:2030962; rev:1; metadata:attack_target Client_Endpoint, created_at 2020_10_05, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_10_05, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)