alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"🐾 - ℹ Thunderbird 🕊 Email client 📧"; flow:to_server, stateless; threshold:type limit, track by_src,count 1, seconds 86400; http.user_agent; content:"Mozilla/5.0"; nocase; content:"Thunderbird/"; nocase; reference:url,https://www.thunderbird.net/; metadata:created_at 2022_02_14, updated_at 2022_06_15; sid:3300788; rev:2; classtype:misc-activity;)