alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Trojan-Dropper.Win32.Small.avu HTTP Checkin"; flow:established,to_server; http.uri; content:"m="; content:"&a="; content:"&r="; content:"&os="; content:"00000"; pcre:"/\/s_\d\d_\d+\?/"; pcre:"/&os=[0-9a-z]{40}/i"; classtype:command-and-control; sid:2008412; rev:6; metadata:created_at 2010_07_30, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_04_18;)