alert tcp $EXTERNAL_NET $HTTP_PORTS -> $HOME_NET any (msg:"ET RETIRED W32/NSIS.TrojanDownloader Second Stage Download Instructions from Server"; flow:established,to_client; content:"|3B 20|Ini download file modue"; nocase; fast_pattern; content:"DownUrl="; nocase; distance:0; content:"FileName="; nocase; distance:0; content:"SaveType="; nocase; distance:0; pcre:"/FileName\x3D[^\r\n]*\x2E(dll|exe)/i"; reference:md5,3ce5da32903b52394cff2517df51f599; classtype:trojan-activity; sid:2014312; rev:4; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_and_Server, tls_state plaintext, created_at 2012_03_06, deployment Perimeter, deployment Internal, former_category MALWARE, malware_family W32_NSIS_TrojanDownloader, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_12_05, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel; target:dest_ip;)