alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE W32/Asprox CnC Beacon"; flow:established,to_server; http.host; pcre:"/\x3a\d{1,5}$/"; http.user_agent; content:"Mozilla/4.0 (compatible|3B| MSIE 6.0b|3B| Windows NT 5.0|3B| .NET CLR"; fast_pattern; http.uri; pcre:"/^\x2F[a-f0-9]{40,60}$/i"; reference:url,www.trendmicro.com/cloud-content/us/pdfs/security-intelligence/white-papers/wp-asprox-reborn.pdf; classtype:command-and-control; sid:2016528; rev:8; metadata:attack_target Client_Endpoint, created_at 2013_03_05, deployment Perimeter, signature_severity Major, tag c2, updated_at 2020_12_10, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)