alert http $EXTERNAL_NET any -> [$HOME_NET,$HTTP_SERVERS] any (msg:"ET MALWARE BadCandy Cisco IOS XE Implant Check-in"; 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:2048584; rev:3; metadata:affected_product Cisco_IOS, attack_target Web_Server, created_at 2023_10_17, cve CVE_2023_20198, deployment Perimeter, deployment Internet, deployment SSLDecrypt, former_category EXPLOIT, confidence High, signature_severity Major, tag CISA_KEV, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2026_10_21, reviewed_at 2024_01_26; target:dest_ip;)