alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/Malgent!MSR User-Agent"; flow:established,to_server; http.user_agent; content:"Not a Virus Download A"; bsize:22; fast_pattern; http.header_names; content:!"Referer"; reference:md5,4c1e57a0388a703307319d17ae5e9039; classtype:trojan-activity; sid:2033747; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_08_19, deployment Perimeter, malware_family Win32_Malgent_MSR, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_08_19;)