Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2018.2631
Ghostscript -- arbitrary code execution
5 September 2018
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: ghostscript
Publisher: CERT/CC
Operating System: UNIX variants (UNIX, Linux, OSX)
Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated
Denial of Service -- Remote/Unauthenticated
Resolution: Mitigation
Original Bulletin:
https://www.kb.cert.org/vuls/id/332928
- --------------------------BEGIN INCLUDED TEXT--------------------
Vulnerability Note VU#332928
Ghostscript contains multiple -dSAFER sandbox bypass vulnerabilities
Original Release date: 21 Aug 2018 | Last revised: 04 Sep 2018
Overview
Ghostscript contains multiple -dSAFER sandbox bypass vulnerabilities, which may
allow a remote, unauthenticated attacker to execute arbitrary commands on a
vulnerable system.
Description
Ghostscript contains an optional -dSAFER option, which is supposed to prevent
unsafe PostScript operations. Multiple PostScript operations bypass the
protections provided by -dSAFER, which can allow an attacker to execute
arbitrary commands with arbitrary arguments. This vulnerability can also be
exploited in applications that leverage Ghostscript, such as ImageMagick,
GraphicsMagick, evince, Okular, Nautilus, and others.
Exploit code for this vulnerability is publicly available.
Impact
By causing Ghostscript or a program that leverages Ghostscript to parse a
specially-crafted file, a remote, unauthenticated attacker may be able to
execute arbitrary commands with the privileges of the Ghostscript code. This
action may be triggered with actions as simple as downloading a file from a
website.
Solution
The CERT/CC is currently unaware of a practical solution to this problem.
Please consider the following workarounds:
Disable PS, EPS, PDF, and XPS coders in ImageMagick policy.xml
ImageMagick uses Ghostscript by default to process PostScript content.
ImageMagick can be controlled via the policy.xml security policy to disable
the processing of PS, EPS, PDF, and XPS content. For example, this can be done
by adding these lines to the <policymap> section of the /etc/ImageMagick/
policy.xml file on a RedHat system:
<policy domain="coder" rights="none" pattern="PS" />
<policy domain="coder" rights="none" pattern="PS2" />
<policy domain="coder" rights="none" pattern="PS3" />
<policy domain="coder" rights="none" pattern="EPS" />
<policy domain="coder" rights="none" pattern="PDF" />
<policy domain="coder" rights="none" pattern="XPS" />
Check with your vendor for the proper location of this file on your platform.
Note that this workaround only mitigates the ImageMagick attack vector to
Ghostscript.
Remove Ghostscript
Because of the number of different attack vectors to get to Ghostscript and the
public availability of exploit code, the most effective protection for this
vulnerability is to remove Ghostscript from your system until a fixed version
is available.
Patch Ghostscript
Artifex software has made the following patches available for Ghostscript:
http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=b575e1ec
http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=8e9ce501
http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=241d9111
http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=c432131c
http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=e01e77a3
http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=0edd3d6c
http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=a054156d
http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=0d390118
http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=c3476dde
http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=b326a716
http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=78911a01
http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=5516c614
Vendor Information (Learn More)
Vendor Status Date Notified Date Updated
Artifex Software, Inc. Affected 24 Aug 2018 24 Aug 2018
CentOS Affected 21 Aug 2018 22 Aug 2018
Debian GNU/Linux Affected 21 Aug 2018 22 Aug 2018
Fedora Project Affected 21 Aug 2018 22 Aug 2018
FreeBSD Project Affected 21 Aug 2018 22 Aug 2018
Gentoo Linux Affected 21 Aug 2018 22 Aug 2018
ImageMagick Affected 24 Aug 2018 24 Aug 2018
Red Hat, Inc. Affected 21 Aug 2018 21 Aug 2018
SUSE Linux Affected 21 Aug 2018 22 Aug 2018
Synology Affected - 23 Aug 2018
Ubuntu Affected 21 Aug 2018 21 Aug 2018
Apple Not Affected 21 Aug 2018 27 Aug 2018
CoreOS Not Affected 21 Aug 2018 21 Aug 2018
Arch Linux Unknown 21 Aug 2018 21 Aug 2018
Arista Networks, Inc. Unknown 21 Aug 2018 21 Aug 2018
If you are a vendor and your product is affected, let us know.View More »
CVSS Metrics (Learn More)
Group Score Vector
Base 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
Temporal 6.8 E:F/RL:W/RC:C
Environmental 6.8 CDP:ND/TD:ND/CR:ND/IR:ND/AR:ND
References
o http://openwall.com/lists/oss-security/2018/08/21/2
o https://bugs.chromium.org/p/project-zero/issues/detail-id=1640
o https://www.imagemagick.org/script/security-policy.php
o https://www.imagemagick.org/script/resources.php
o https://www.ghostscript.com/doc/current/Use.htm#Safer
o http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=b575e1ec
o http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=8e9ce501
o http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=241d9111
o http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=c432131c
o http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=e01e77a3
o http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=e01e77a3
o http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=0edd3d6c
o http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=a054156d
o http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=0d390118
o http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=c3476dde
o http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=b326a716
o http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=78911a01
o http://git.ghostscript.com/-p=ghostpdl.git;a=commitdiff;h=5516c614
Credit
This vulnerability was publicly disclosed by Tavis Ormandy.
This document was written by Will Dormann.
Other Information
o CVE IDs: Unknown
o Date Public: 21 Feb 2018
o Date First Published: 21 Aug 2018
o Date Last Updated: 04 Sep 2018
o Document Revision: 44
- --------------------------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 auscert@auscert.org.au
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:
https://www.auscert.org.au/bulletins/
===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072
Internet Email: auscert@auscert.org.au
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.
===========================================================================
-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967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=FrNP
-----END PGP SIGNATURE-----