Description: LSS Security Team has reported a weakness in ProFTPD, which potentially can be exploited by malicious people to determine valid usernames.
The problem is that there is a time delay difference in the login process for existing and non-existing usernames. This can be exploited to determine valid user accounts and potentially their privileges by sending some "USER" commands and calculating the response period.
The weakness has been reported in version 1.2.x. Other versions may also be affected.
Solution: The weakness has been fixed in version 1.3.0rc1 with the introduction of the mod_delay module.
Provided and/or discovered by: LSS Security Team
Changelog: 2004-11-11: Added information about "mod_delay" module.
2005-02-22: Added CVE reference.
2006-01-17: Updated "Solution Status" and "Solution" sections.
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