alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET EXPLOIT Cisco IOS XE Web Server Implant Check (CVE-2023-20198) (Outbound) M1"; flow:established,to_server; urilen:38; http.method; content:"POST"; http.uri; content:"/webui/logoutconfirm.html?logon_hash=1"; fast_pattern; threshold:type limit,seconds 300,count 1,track by_src; reference:url,blog.talosintelligence.com/active-exploitation-of-cisco-ios-xe-software/; reference:cve,2023-20198; classtype:trojan-activity; sid:2048583; rev:2; metadata:affected_product iOS, attack_target Web_Server, created_at 2023_10_17, cve CVE_2023_20198, deployment Perimeter, deployment SSLDecrypt, confidence High, signature_severity Major, tag CISA_KEV, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_10_30, reviewed_at 2024_01_26;)