alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE SEASALT HTTP Checkin"; flow:established,to_server; http.user_agent; content:"Mozilla/4.0 (compatible|3b 20|MSIE 5.00|3b 20|Windows 98) KSMM"; fast_pattern; bsize:52; reference:md5,5e0df5b28a349d46ac8cc7d9e5e61a96; reference:url,www.mandiant.com/apt1; classtype:command-and-control; sid:2016440; rev:3; metadata:created_at 2013_02_20, signature_severity Major, updated_at 2020_04_23;)