alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/TrickBot Anchor Variant Style External IP Check"; flow:established,to_server; http.method; content:"GET"; urilen:1; http.user_agent; content:"WinHTTP loader/"; fast_pattern; startswith; http.host; bsize:21; content:"checkip.amazonaws.com"; http.header_names; to_lowercase; content:!"|0d 0a|referer|0d 0a|"; reference:md5,730b66cd89c8b4751dbe2c5158701a0b; classtype:trojan-activity; sid:2032216; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_11_16, deployment Perimeter, malware_family AnchorTrickBot, confidence High, signature_severity Major, updated_at 2024_04_29;)