alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (msg:"ET WEB_SPECIFIC_APPS Ubiquiti Unifi OS Path Traversal (CVE-2026-34909)"; flow:established,to_server; http.uri; content:"/proxy/users/public/avatar/"; fast_pattern; startswith; content:"filename|3d|"; pcre:"/^[^&]*?(?:(?:\x2e|%+(?:25)?2[Ee]|%+(?:25)?32%+(?:25)?[46]5){1,2}(?:\x2f|\x5c|%+(?:25)?(?:25)?5[Cc]|%+(?:25)?2[Ff]){1,}){2,}/R"; reference:url,www.boredhackerblog.info/2026/06/how-unifi-os-exploitation-may-have.html; reference:url,bishopfox.com/blog/popping-root-on-unifi-os-server-unauthenticated-rce-chain-detection-analysis; reference:cve,2026-34909; classtype:web-application-attack; sid:2069921; rev:1; metadata:affected_product Ubiquiti, attack_target Server, tls_state TLSDecrypt, created_at 2026_06_12, cve CVE_2026_34909, deployment Perimeter, deployment Internal, deployment SSLDecrypt, confidence High, signature_severity Major, tag Exploit, updated_at 2026_06_12, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application; target:dest_ip;)