alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE LegionLoader Activity Observed (LegionClient)"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/api-v1"; http.user_agent; content:"LegionClient"; fast_pattern; http.header_names; content:!"Referer"; content:"|0d 0a|pauthx|0d 0a|"; classtype:trojan-activity; sid:2046298; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2023_06_16, deployment Perimeter, deployment SSLDecrypt, malware_family LegionLoader, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_06_22, reviewed_at 2025_07_14; target:src_ip;)