alert tcp $TELNET_SERVERS 23 -> $EXTERNAL_NET any (msg:"GPL TELNET TELNET access"; flow:from_server,established; content:"|FF FD|"; rawbytes; content:"|FF FD|"; distance:0; rawbytes; content:"|FF FD|"; distance:0; rawbytes; reference:arachnids,08; reference:cve,1999-0619; reference:nessus,10280; classtype:not-suspicious; sid:2100716; rev:14; metadata:created_at 2010_09_23, signature_severity Unknown, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)