axl has discovered multiple vulnerabilities in WFTPD Server and WFTPD Pro Server, which can be exploited by malicious users to compromise a vulnerable system and cause a DoS (Denial of Service).

1) A boundary error within a routine for handling arguments supplied to the "LIST", "NLST", and "STAT" FTP commands can be exploited to cause a buffer overflow. This can be achieved by passing a specially crafted argument, which starts with the "-" character followed by an overly long string and a space, to any of the affected commands.

Successful exploitation may allow execution of arbitrary code with the privileges of the FTP server.

The vulnerability has been reported in the following versions:

* WFTPD Pro Server 3.21 Release 1
* WFTPD Pro Server 3.20 Release 2
* WFTPD Server 3.21 Release 1
* WFTPD Server 3.10 Release 1

2) Various errors within the routines for handling FTP commands can be exploited to cause the FTP server to consume 100% CPU and memory resources and eventually crash it by sending extremely large amounts of data without terminating characters.

3) When the option "XeroxDocutech" is set to "1", an off-by-one error can be exploited to crash the FTP server by supplying a specially crafted "MKD" or "XMKD" FTP command.

The DoS vulnerabilities have been reported in WFTPD Pro Server 3.21 Release 1. Other versions may also be affected.

Solution
The vulnerabilities have reportedly been fixed in the following versions:
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Provided and/or discovered by
axl

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