alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed TA399/SideWinder User-Agent"; flow:established,to_server; http.user_agent; content:"Mozilla/4.0 (compatible|3b 20|Win32|3b 20|WinHttp.WinHttpRequest.56)"; bsize:58; reference:url,medium.com/@Sebdraven/apt-sidewinder-complicates-theirs-malwares-4e15683e7e26; classtype:trojan-activity; sid:2029825; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_04_07, deployment Perimeter, malware_family Sidewinder, confidence High, signature_severity Major, tag TA399, updated_at 2020_04_07;)