alert http1 $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Possible OSX/SHLAYER Checkin M2"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/rga?a="; startswith; fast_pattern; content:"&b="; within:10; pcre:"/^[A-F0-9]{8}\-[A-F0-9]{4}\-[A-F0-9]{4}\-[A-F0-9]{4}\-[A-F0-9]{12}$/R"; http.user_agent; content:"Go-http-client/1.1"; http.header_names; bsize:39; content:"|0d 0a|Host|0d 0a|User-Agent|0d 0a|Accept-Encoding|0d 0a 0d 0a|"; threshold:type limit, count 1, seconds 600, track by_dst; classtype:trojan-activity; sid:2038613; rev:3; metadata:affected_product Mac_OSX, attack_target Client_Endpoint, created_at 2022_08_25, deployment Perimeter, malware_family Shlayer, performance_impact Low, confidence Low, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_03;)