alert tcp-pkt $HOME_NET any -> $EXTERNAL_NET ![80,443,444,3128,4339,8001,8080,8443,9001,54443] (msg:"ET MALWARE Possible ToneShell CnC Checkin M1"; flow:established,to_server; dsize:<500; content:"|17 03 03|"; fast_pattern; startswith; byte_jump:2,0,relative,post_offset 4; isdataat:!2,relative; pcre:"/^\x17\x03\x03.{2}[\x00\x01]/"; reference:url,www.trendmicro.com/en_us/research/22/k/earth-preta-spear-phishing-governments-worldwide.html; classtype:trojan-activity; sid:2048241; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_and_Server, created_at 2023_09_25, deployment Perimeter, deprecation_reason Performance, malware_family Toneshell, performance_impact Significant, confidence Low, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_09_27, reviewed_at 2023_09_27; target:src_ip;)