WzdFTPD < 8.1 Denial of service

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                  - S21Sec Advisory -

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 Title:   WzdFTPD Denial of Service
    ID:   S21SEC-033-en

Severity: Medium - Denial of Service
History: 26.Dic.2006 Vulnerability discovered
8.Ene.2007 Vendor contacted

 Scope:   FTP Server Denial of Service

Platforms: Any
Author: Jose Miguel Esparza ([email protected])
URL: http://www.s21sec.com/avisos/s21sec-033-en.txt
Release: Public

[ SUMMARY ]

WzdFTPD is a ftp server designed to be modular and portable, work
under linux/win32/freebsd/openbsd, and to be entirely configurable
online using SITE commands. It supports SSL, IPv6, multithreading,
external scripts, and it uses Unix-like permissions and ACLs, with
virtual users and groups.

WzdFTPD project also supports bandwith limitation (per user, per
group, or globally), group administrators, and per command
authorization.

[ AFFECTED VERSIONS ]

Following versions are affected with this issue:

    - WzdFTPD v8.0 and prior.
     - Lastest version (8.1) is not affected by this vulnerability.

[ DESCRIPTION ]

It's possible to cause a denial of service sending a special crafted
FTP command.

[ WORKAROUND ]

Add "key != NULL" condition in the chtbl_lookup function of the
hash.c file until vendor solution or upgrade to 8.1.

[ ACKNOWLEDGMENTS ]

These vulnerabilities have been found and researched by:

    - Jose Miguel Esparza <[email protected]> S21Sec

With thanks to:

    - David Barroso <[email protected]> S21Sec    

[ REFERENCES ]

• WzdFTPD
  http://www.wzdftpd.net/

• S21Sec
  http://www.s21sec.com