alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Backdoor.Elise Style IP Check M2"; flow:established,to_server; urilen:16; http.uri; content:"/myip?format=txt"; http.user_agent; content:"User-Agent|3a 20|Mozilla/4.0 (compatible|3b 20|MSIE 7.0|3b 20|Win32)"; startswith; http.host; content:"api.ipaddress.com"; fast_pattern; http.header_names; content:"|0d 0a|Connection|0d 0a|User-Agent|0d 0a|Host|0d 0a 0d 0a|"; classtype:trojan-activity; sid:2030229; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_05_29, deployment Perimeter, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_03_12;)