alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET RETIRED Malvirt/KoiVM Downloader Variant Payload Retrieval Request"; flow:established, to_server; dsize:38; stream_size:client,=,39; content:"get_"; fast_pattern; startswith; pcre:"/^[a-f0-9]{32}\x0d\x0a$/R"; reference:md5,dad996ac644cafb4c238bbd162945114; reference:url,scribe.froth.zone/walmartglobaltech/malvert-koivm-downloader-variant-ed4a88920b8c; reference:url,www.sentinelone.com/labs/malvirt-net-virtualization-thrives-in-malvertising-attacks/; classtype:trojan-activity; sid:2044003; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2023_01_26, deployment Perimeter, former_category MALWARE, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_09_30, reviewed_at 2024_09_30;)