copyright | disclaimer | privacy | contact  
Australia's Leading Computer Emergency Response Team
Search this site

On this site

 > About AusCERT
 > Membership
 > Contact Us
 > PKI Services
 > Publications
 > Sec. Bulletins
 > Conferences
 > News & Media
 > Services
 > Web Log
 > Site Map
 > Site Help
 > Member login


ESB-2007.0964 -- [FreeBSD] -- gtar directory traversal vulnerability

Date: 30 November 2007
References: ESB-2007.0641  

Click here for printable version
Click here for PGP verifiable version
Hash: SHA1

             AUSCERT External Security Bulletin Redistribution

                        ESB-2007.0964 -- [FreeBSD]
                  gtar directory traversal vulnerability
                             30 November 2007


        AusCERT Security Bulletin Summary

Product:              gtar
Publisher:            FreeBSD
Operating System:     FreeBSD
Impact:               Modify Arbitrary Files
Access:               Remote/Unauthenticated
CVE Names:            CVE-2007-4131

Ref:                  ESB-2007.0641

Original Bulletin:

- --------------------------BEGIN INCLUDED TEXT--------------------

Hash: SHA1

FreeBSD-SA-07:10.gtar                                       Security Advisory
                                                          The FreeBSD Project

Topic:          gtar directory traversal vulnerability

Category:       contrib
Module:         contrib_tar
Announced:      2007-11-29
Credits:        Dmitry V. Levinx
Affects:        FreeBSD 5.x releases
Corrected:      2007-11-29 16:08:54 UTC (RELENG_5, 5.5-STABLE)
                2007-11-29 16:09:26 UTC (RELENG_5_5, 5.5-RELEASE-p17)
CVE Name:       CVE-2007-4131

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:>.

I.   Background

GNU tar (gtar) is a utility to create and extract "tape archives",
commonly known as tar files.  GNU tar is included in FreeBSD 5.x as

II.  Problem Description

Insufficient sanity checking of paths containing '.' and '..' allows
gtar to overwrite arbitrary files on the system.

III. Impact

An attacker who can convince an user to extract a specially crafted
archive can overwrite arbitrary files with the permissions of the user
running gtar.  If that user is root, the attacker can overwrite any
file on the system.

IV.  Workaround

Use "bsdtar", which has been the default tar implementation since
FreeBSD 5.3.

V.   Solution

Perform one of the following:

1) Upgrade your vulnerable system to 5-STABLE, or to the RELENG_5_5
security branch dated after the correction date.

2) To patch your present system:

The following patches have been verified to apply to FreeBSD 5.5

a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.

# fetch
# fetch

b) Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch
# cd /usr/src/gnu/usr.bin/tar
# make obj && make depend && make && make install

VI.  Correction details

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

Branch                                                           Revision
- - -------------------------------------------------------------------------
  src/UPDATING                                            1.342.
- - -------------------------------------------------------------------------

VII. References

The latest revision of this advisory is available at
Version: GnuPG v1.4.7 (FreeBSD)


- --------------------------END INCLUDED TEXT--------------------

You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to
and we will forward your request to the appropriate person.

NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.

NOTE: This is only the original release of the security bulletin.  It may
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:

If you believe that your computer system has been compromised or attacked in 
any way, we encourage you to let us know by completing the secure National IT 
Incident Reporting Form at:

Australian Computer Emergency Response Team
The University of Queensland
Qld 4072

Internet Email:
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
                AusCERT personnel answer during Queensland business hours
                which are GMT+10:00 (AEST).
                On call after hours for member emergencies only.