alert http any any -> $HOME_NET any (msg:"ET EXPLOIT [CORELIGHT] - CVE-2025-27218 Sitecore unsafe deserialization attempt"; flow:established,to_server; http.header; header_lowercase; content:"thumbnailsaccesstoken|3a 20|"; nocase; content:"AQAAAAAAAAAEAQAAAClTeXN0ZW0uU2VjdXJpdHkuUHJpbmNpcGF"; fast_pattern; distance:0; reference:url,slcyber.io/blog/sitecore-unsafe-deserialization-again-cve-2025-27218/; reference:cve,2025-27218; classtype:attempted-admin; sid:2060777; rev:2; metadata:attack_target Server, created_at 2025_03_10, cve CVE_2025_27218, deployment Perimeter, deployment Internal, confidence High, signature_severity Major, tag Exploit, updated_at 2025_03_28, reviewed_at 2025_08_06, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application; target:dest_ip;)