alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET EXPLOIT Cisco IOS XE Web Server Auth Bypass (CVE-2023-20198) (Inbound) M2"; flow:established,to_server; flowbits:set,ET.CVE-2023-20198.Inbound; http.method; content:"GET"; http.uri.raw; content:"/|25|25"; startswith; fast_pattern; threshold:type limit,seconds 300,count 1,track by_src; reference:url,github.com/fox-it/cisco-ios-xe-implant-detection; reference:cve,2023-20198; classtype:attempted-recon; sid:2048738; rev:3; metadata:attack_target Networking_Equipment, created_at 2023_10_23, cve CVE_2023_20198, deployment Perimeter, deployment SSLDecrypt, performance_impact Significant, confidence Medium, signature_severity Major, tag CISA_KEV, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_03_14, reviewed_at 2023_10_30;)