alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET EXPLOIT Zyxel NAS RCE Attempt Inbound (CVE-2020-9054) M2"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/adv,/cgi-bin/weblogin.cgi"; startswith; fast_pattern; http.request_body; content:"username="; startswith; pcre:"/^.{0,18}(?:\x27|%27)(?:\x3b|%3[Bb])/R"; reference:cve,2020-9054; reference:url,www.zyxel.com/support/remote-code-execution-vulnerability-of-NAS-products.shtml; reference:url,www.kb.cert.org/vuls/id/498544/; classtype:attempted-admin; sid:2029617; rev:3; metadata:attack_target Networking_Equipment, created_at 2020_03_12, cve CVE_2020_9054, deployment Perimeter, confidence Medium, signature_severity Major, tag CISA_KEV, updated_at 2025_07_10;)