alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE NOBELIUM (TA421) EnvyScout Fingerprint Checkin"; flow:established,to_server; http.method; content:"POST"; http.content_type; content:"application/json"; bsize:16; http.request_body; content:"|7b 22|io|22 3a 22|"; startswith; fast_pattern; content:"|22 2c 22|tu|22 3a 22|"; distance:0; content:"|22 2c 22|sd|22 3a 22|"; distance:0; reference:url,www.microsoft.com/security/blog/2021/05/27/new-sophisticated-email-based-attack-from-nobelium/; reference:url,www.microsoft.com/security/blog/2021/05/28/breaking-down-nobeliums-latest-early-stage-toolset; classtype:command-and-control; sid:2033052; rev:3; metadata:affected_product Web_Browsers, attack_target Client_Endpoint, created_at 2021_05_28, deployment Perimeter, malware_family EnvyScout, confidence High, signature_severity Major, updated_at 2021_12_07;)