alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Ransom.Win32.Blocker.fwlm Checkin"; flow:established,to_server; urilen:497; http.method; content:"GET"; http.uri; content:".bin"; fast_pattern; pcre:"/^\/(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})\.bin$/"; http.header_names; content:!"Referer|0d 0a|"; reference:url,vxsecurity.sg/2014/10/25/technical-teardown-hongkong-protest-malware/; classtype:command-and-control; sid:2019538; rev:5; metadata:created_at 2014_10_28, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_11_19;)