alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET HUNTING Suspicious User-Agent (Random String)"; flow:established,to_server; http.user_agent; content:"Random String"; bsize:13; reference:md5,a1e56bd465d1c1b5fc19384a3a7ec461; classtype:trojan-activity; sid:2028947; rev:1; metadata:attack_target Client_Endpoint, created_at 2019_11_07, deployment Perimeter, performance_impact Low, confidence Medium, signature_severity Informational, updated_at 2019_11_07;)