alert tcp $EXTERNAL_NET any -> $HOME_NET 21 (msg:"GPL FTP CWD ~root attempt"; flow:to_server,established; content:"CWD"; nocase; content:"~root"; distance:1; nocase; pcre:"/^CWD\s+~root/smi"; reference:arachnids,318; reference:cve,1999-0082; classtype:bad-unknown; sid:2100336; rev:11; metadata:created_at 2010_09_23, cve CVE_1999_0082, signature_severity Minor, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)