alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (msg:"ET EXPLOIT Possible Moxa MxView RCE Attempt (CVE-2021-38454)"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"api/sites/site/"; fast_pattern; pcre:"/^[a-zA-Z0-9]{5,45}/R"; content:"/ping"; endswith; reference:cve,2021-38454; classtype:attempted-admin; sid:2035194; rev:2; metadata:attack_target Server, created_at 2022_02_14, cve CVE_2021_38454, deployment Perimeter, deployment Internal, confidence Medium, signature_severity Major, tag Exploit, updated_at 2022_02_14, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application;)