alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Ransom.Win32.Birele.gsg Checkin"; flow:established,to_server; http.uri; content:".html"; pcre:"/^\/\d+?\/\d+?\.html$/i"; http.header; content:"From|3a| "; depth:6; pcre:"/^\d+?\r\n/Ri"; content:"Via|3a| "; content:!"1|2e|"; within:2; http.header_names; content:!"User-Agent|0d 0a|"; reference:md5,116aaaa5765228d61501322b02a6a3b1; reference:md5,2e66f39a263cb2e95425847b60ee2a93; reference:md5,0ea9b34e9d77b5a4ef5170406ed1aaed; classtype:command-and-control; sid:2015786; rev:5; metadata:created_at 2012_10_10, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_12_18;)