AusCERT - ESB-2001.521 -- FreeBSD-SA-01:64.wu-ftpd -- wu-ftpd port contains remote root compromise

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ESB-2001.521 -- FreeBSD-SA-01:64.wu-ftpd -- wu-ftpd port contains remote root compromise
Date: 06 December 2001
References: ESB-2001.507

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===========================================================================
             AUSCERT External Security Bulletin Redistribution

                 ESB-2001.521 -- FreeBSD-SA-01:64.wu-ftpd
               wu-ftpd port contains remote root compromise
                              6 December 2001

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:                wu-ftpd
Vendor:                 FreeBSD Ports Collection
Operating System:       FreeBSD
Impact:                 Root Compromise
                        Denial of Service
Access Required:        Existing Account

Ref:                    AA-2001.05
                        ESB-2001.507

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=============================================================================
FreeBSD-SA-01:64                                           Security Advisory
                                                                FreeBSD, Inc.

Topic:          wu-ftpd port contains remote root compromise

Category:       ports
Module:         wu-ftpd
Announced:      2001-12-04
Credits:        CORE Security Technologies
                Contact: Ivan Arce (iarce@corest.com)
Affects:        Ports collection prior to the correction date
Corrected:      2001-11-28 10:52:26 UTC
FreeBSD only:   NO

I.   Background

wu-ftpd is a popular full-featured FTP server.

II.  Problem Description

The wu-ftpd port, versions prior to wu-ftpd-2.6.1_7, contains a
vulnerability which allows FTP users, both anonymous FTP users and
those with valid accounts, to execute arbitrary code as root on
the local machine.  This may be accomplished by inserting invalid
globbing parameters which are incorrectly parsed by the FTP server
into command input.

The wu-ftpd port is not installed by default, nor is it "part of
FreeBSD" as such: it is part of the FreeBSD ports collection, which
contains over 6000 third-party applications in a ready-to-install
format. The ports collection shipped with FreeBSD 4.4 contains this
problem since it was discovered after the release.

FreeBSD makes no claim about the security of these third-party
applications, although an effort is underway to provide a security
audit of the most security-critical ports.

III. Impact

FTP users, including anonymous FTP users, can cause arbitrary commands
to be executed as root on the local machine.

If you have not chosen to install the wu-ftpd port/package, then your
system is not vulnerable to this problem.

IV.  Workaround

Deinstall the wu-ftpd port/package, if you have installed it.

V.   Solution

One of the following:

1) Upgrade your entire ports collection and rebuild the wu-ftpd port.

2) Deinstall the old package and install a new package dated after the
correction date, obtained from:

[i386]
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/ftp/wu-ftpd-2.6.1_7.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/ftp/wu-ftpd-2.6.1_7.tgz

[alpha]
Packages are not automatically generated for the alpha architecture at
this time due to lack of build resources

NOTE: It may be several days before updated packages are available. Be
sure to check the file creation date on the package, because the
version number of the software has not changed.

3) download a new port skeleton for the wu-ftpd port from:

http://www.freebsd.org/ports/

and use it to rebuild the port.

4) Use the portcheckout utility to automate option (3) above. The
portcheckout port is available in /usr/ports/devel/portcheckout or the
package can be obtained from:

ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/devel/portcheckout-2.0.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/devel/portcheckout-2.0.tgz

VI.  Correction details

The following list contains the revision numbers of each file that was
corrected in the FreeBSD ports collection.

Path                                                             Revision
- - -------------------------------------------------------------------------
ports/ftp/wu-ftpd/Makefile                                         1.41
ports/ftp/wu-ftpd/files/patch-ap                                   1.2
- - -------------------------------------------------------------------------

VII. References

<URL:http://www.securityfocus.com/archive/1/242750>

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