alert ftp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET DELETED Kimsuky Related FTP File Download"; flow:established,to_server; content:"RETR|20|/mongo/"; fast_pattern; pcre:"/[a-z]{8}.(:?tif|gif)/Ri"; classtype:trojan-activity; sid:2034513; rev:2; metadata:attack_target Client_Endpoint, created_at 2021_11_18, performance_impact Low, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_11_18;)