alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET USER_AGENTS Suspicious User Agent (KtulhuBrowser)"; flow:established,to_server; http.user_agent; bsize:13; content:"KtulhuBrowser"; nocase; classtype:bad-unknown; sid:2029750; rev:2; metadata:attack_target Client_Endpoint, created_at 2020_03_27, deployment Perimeter, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_08_19;)