alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Scieron Retrieving Information Response"; flow:established,from_server; file_data; content:"system"; within:6; pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})system$/R"; flowbits:isset,ET.Trojan.Scieron.Ret; reference:url,symantec.com/connect/blogs/scarab-attackers-took-aim-select-russian-targets-2012; reference:md5,a36db258d0f6f085e8e5030d8e9a9bf4; classtype:trojan-activity; sid:2020297; rev:2; metadata:created_at 2015_01_23, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)