BlackMoon FTP Server 2.6 Free Edition, and possibly other distributions and versions, generates an "Account does not exist" error message when an invalid username is entered, which makes it easier for remote attackers to conduct brute force attacks.
http://marc.info/?l=bugtraq&m=105353283720837&w=2
Source: Mitre, NVD
Published: 2003-05-21
Updated: 2016-10-18
Base Score: 4.6
Vector: CVSS2#AV:L/AC:L/Au:N/C:P/I:P/A:P
Severity: Medium
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: Critical