alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Winter Vivern APT Aperetif Payload Retrieval Attempt M2"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"signatures.php?id=1"; fast_pattern; reference:url,www.sentinelone.com/labs/winter-vivern-uncovering-a-wave-of-global-espionage/; classtype:trojan-activity; sid:2044664; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2023_03_16, deployment Perimeter, deployment SSLDecrypt, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_03_16;)