The remote administration client for RhinoSoft Serv-U 3.0 sends the user password in plaintext even when S/KEY One-Time Password (OTP) authentication is enabled, which allows remote attackers to sniff passwords.
https://exchange.xforce.ibmcloud.com/vulnerabilities/7925
https://euvd.enisa.europa.eu/vulnerability/EUVD-2001-1443