alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE APT Lazarus Nukesped Downloader"; flow:established,to_server; http.method; content:"POST"; http.uri; content:".asp"; endswith; http.accept_lang; content:"ko-KR|3b|q|3d|"; startswith; http.request_body; content:"fn="; startswith; nocase; content:".gif&code="; nocase; distance:0; fast_pattern; pcre:"/^fn=[^&]*\.gif&code=\d+$/i"; reference:url,www.welivesecurity.com/2020/11/16/lazarus-supply-chain-attack-south-korea/; classtype:command-and-control; sid:2031207; rev:4; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_11_16, deployment Perimeter, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_05_01;)