alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Innostealer Domain (windows11-upgrade .com) in TLS SNI"; flow:established,to_server; tls.sni; content:"windows11-upgrade"; startswith; fast_pattern; pcre:"/[0-9]{1,2}/R"; content:".com"; endswith; reference:url,twitter.com/JAMESWT_MHT/status/1517822757567971329; reference:url,www.bleepingcomputer.com/news/security/unofficial-windows-11-upgrade-installs-info-stealing-malware/; classtype:trojan-activity; sid:2036366; rev:2; metadata:attack_target Client_Endpoint, created_at 2022_04_25, deployment Perimeter, deprecation_reason Age, malware_family Innostealer, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_08_21, reviewed_at 2023_08_21;)