alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET USER_AGENTS Kimsuky CnC Checkin User-Agent"; flow:established,to_server; http.user_agent; content:"Mozilla|2f|5|2e|0|20 28|Windows|20|NT|20|10|2e|x|3b 20|Win64|3b 20|x64|29 20|AppleWebKit|2f|537|2e|36|20 28|KHTML|2c 20|like|20|Gecko|29 20|Chremo|2f|87|2e|0|2e|4280|2e|141|20|Safari|2f|537|2e|36|20|Edgo|2f|87|2e|0|2e|664|2e|75"; bsize:132; fast_pattern; reference:url,zhuanlan.zhihu.com/p/567386930; classtype:trojan-activity; sid:2046893; rev:1; metadata:attack_target Client_Endpoint, created_at 2023_07_25, deployment Perimeter, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_07_25;)