alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET EXPLOIT_KIT CottonCastle/Niteris EK POST Beacon April 29 2015"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"0/"; pcre:"/^\/[a-z]+\/[a-z]+\//"; http.content_type; bsize:33; content:"application/x-www-form-urlencoded"; fast_pattern; http.request_body; content:"%"; pcre:"/^-?\d+=(?:[a-zA-Z0-9]|%[A-F0-9]{2}){2}(?P<var1>(?:[a-zA-Z0-9]|%[A-F0-9]{2}))(?:[a-zA-Z0-9]|%[A-F0-9]{2}){6}(?P<var2>(?:[a-zA-Z0-9]|%[A-F0-9]{2}))(?:[a-zA-Z0-9]|%[A-F0-9]{2}){2}(?P=var2)(?:[a-zA-Z0-9]|%[A-F0-9]{2}){4}(?P=var1)/P"; classtype:exploit-kit; sid:2021038; rev:6; metadata:attack_target Client_Endpoint, created_at 2015_04_30, deployment Perimeter, confidence High, signature_severity Major, tag c2, updated_at 2024_03_05, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)