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Posted on 05 November 2014
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FreeBSD-SA-14:26.ftp Security Advisory
The FreeBSD Project
Topic: Remote command execution in ftp(1)
Category: core
Module: ftp
Announced: 2014-11-04
Credits: Jared McNeill, Alistair Crooks
Affects: All supported versions of FreeBSD.
Corrected: 2014-11-04 23:29:57 UTC (stable/10, 10.1-PRERELEASE)
2014-11-04 23:34:46 UTC (releng/10.1, 10.1-RC4-p1)
2014-11-04 23:34:46 UTC (releng/10.1, 10.1-RC3-p1)
2014-11-04 23:34:46 UTC (releng/10.1, 10.1-RC2-p3)
2014-11-04 23:31:17 UTC (releng/10.0, 10.0-RELEASE-p12)
2014-11-04 23:30:47 UTC (stable/9, 9.3-STABLE)
2014-11-04 23:33:46 UTC (releng/9.3, 9.3-RELEASE-p5)
2014-11-04 23:33:17 UTC (releng/9.2, 9.2-RELEASE-p15)
2014-11-04 23:32:45 UTC (releng/9.1, 9.1-RELEASE-p22)
2014-11-04 23:30:23 UTC (stable/8, 8.4-STABLE)
2014-11-04 23:32:15 UTC (releng/8.4, 8.4-RELEASE-p19)
CVE Name: CVE-2014-8517
For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:http://security.FreeBSD.org/>.
I. Background
The ftp(1) userland utility is an interactive FTP client. It can also
be used non-interactively, by providing a URL on the command line. In
this mode, it supports HTTP in addition to FTP.
II. Problem Description
A malicious HTTP server could cause ftp(1) to execute arbitrary
commands.
III. Impact
When operating on HTTP URIs, the ftp(1) client follows HTTP redirects,
and uses the part of the path after the last '/' from the last
resource it accesses as the output filename if '-o' is not specified.
If the output file name provided by the server begins with a pipe
('|'), the output is passed to popen(3), which might be used to
execute arbitrary commands on the ftp(1) client machine.
IV. Workaround
No workaround is available. Users are encouraged to replace ftp(1) in
non-interactive use by either fetch(1) or a third-party client such as
curl or wget.
V. Solution
Perform one of the following:
1) Upgrade your vulnerable system to a supported FreeBSD stable or
release / security branch (releng) dated after the correction date.
2) To update your vulnerable system via a binary patch:
Systems running a RELEASE version of FreeBSD on the i386 or amd64
platforms can be updated via the freebsd-update(8) utility:
# freebsd-update fetch
# freebsd-update install
3) To update your vulnerable system via a source code patch:
The following patches have been verified to apply to the applicable
FreeBSD release branches.
a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.
[FreeBSD 8]
# fetch http://security.FreeBSD.org/patches/SA-14:26/ftp-8.patch
# fetch http://security.FreeBSD.org/patches/SA-14:26/ftp-8.patch.asc
# gpg --verify ftp-8.patch.asc
[All other versions]
# fetch http://security.FreeBSD.org/patches/SA-14:26/ftp.patch
# fetch http://security.FreeBSD.org/patches/SA-14:26/ftp.patch.asc
# gpg --verify ftp.patch.asc
b) Apply the patch. Execute the following commands as root:
# cd /usr/src
# patch < /path/to/patch
c) Recompile ftp. Execute the following commands as root:
# cd /usr/src/usr.bin/ftp
# make && make install
VI. Correction details
The following list contains the correction revision numbers for each
affected branch.
Branch/path Revision
- -------------------------------------------------------------------------
stable/8/ r274108
releng/8.4/ r274111
stable/9/ r274109
releng/9.1/ r274112
releng/9.2/ r274113
releng/9.3/ r274114
stable/10/ r274107
releng/10.0/ r274110
releng/10.1/ r274115
- -------------------------------------------------------------------------
To see which files were modified by a particular revision, run the
following command, replacing NNNNNN with the revision number, on a
machine with Subversion installed:
# svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base
Or visit the following URL, replacing NNNNNN with the revision number:
<URL:http://svnweb.freebsd.org/base?view=revision&revision=NNNNNN>
VII. References
<URL:http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-8517>
The latest revision of this advisory is available at
<URL:http://security.FreeBSD.org/advisories/FreeBSD-SA-14:26.ftpd.asc>
