Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2007.0218 -- [UNIX/Linux]
Multiple Vendor X Server vulnerabilities
4 April 2007
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: X servers from multiple vendors
Publisher: iDefense
Operating System: UNIX variants (UNIX, Linux, OSX)
Impact: Increased Privileges
Access: Existing Account
CVE Names: CVE-2007-1003 CVE-2007-1351 CVE-2007-1352
Original Bulletin:
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=501
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=502
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=503
Comment: This alert contains three advisories detailing vulnerabilities in
various X server implementations.
- --------------------------BEGIN INCLUDED TEXT--------------------
Multiple Vendor X Server BDF Font Parsing Integer Overflow Vulnerability
iDefense Security Advisory 04.03.07
http://labs.idefense.com/intelligence/vulnerabilities/
Apr 03, 2007
I. BACKGROUND
The X Window System (or X11) is a graphical windowing system used on
Unix-like systems. It is based on a client/server model. More
information about about The X Window system is available at the
following URL.
http://en.wikipedia.org/wiki/X_Window_System
II. DESCRIPTION
Local exploitation of an integer overflow vulnerability in multiple
vendors' implementations of the X Window System server BDF font parsing
component could allow execution of arbitrary commands with elevated
privileges.
The vulnerability specifically exists in the parsing of BDF fonts. When
the X server encounters a specially crafted BDF font, an integer
overflow occurs leading to a potentially exploitable heap overflow
condition.
III. ANALYSIS
Exploitation allows attackers to execute arbitrary code with elevated
privileges.
As the X11 server requires direct access to video hardware, it runs with
elevated privileges. A user compromising an X server would gain those
permissions.
In order to exploit this vulnerability, an attacker would need to be
able to cause the X server to use a maliciously constructed font. The
X11 server contains multiple methods for a user to define additional
paths to look for fonts. An exploit has been developed using the "-fp"
command line option to the X11 server to pass the location of the
attack to the server. It is also possible to use "xset" command with
the "fp" option to perform an attack on an already running server.
Some distributions allow users to start the X11 server only if they are
logged on at the console, while others will allow any user to start it.
Attempts at exploiting this vulnerability may put the console into an
unusable state. This will not prevent repeated exploitation attempts.
IV. DETECTION
iDefense has confirmed the existence of this vulnerability in X.Org
X11R7.1. Older versions are suspected to be vulnerable. Additionally,
it is reported that the freetype library is also vulnerable.
V. WORKAROUND
iDefense is currently unaware of any effective workaround for this
issue.
VI. VENDOR RESPONSE
The X.Org Foundation has addressed this vulnerability with source code
patches. More information can be found from their advisory at the
following URL.
http://lists.freedesktop.org/archives/xorg-announce/2007-april/0286.html
The freetype developers have committed a fix for this issue to their CVS
repository. Future releases will contain this fix.
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-1351 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
security problems.
VIII. DISCLOSURE TIMELINE
02/21/2007 Initial vendor notification
03/28/2007 Initial vendor response
04/03/2007 Coordinated public disclosure
IX. CREDIT
This vulnerability was discovered by Greg MacManus of iDefense Labs.
Get paid for vulnerability research
http://labs.idefense.com/methodology/vulnerability/vcp.php
Free tools, research and upcoming events
http://labs.idefense.com/
X. LEGAL NOTICES
Copyright © 2007 iDefense, Inc.
Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
written consent of iDefense. If you wish to reprint the whole or any
part of this alert in any other medium other than electronically,
please e-mail customerservice@idefense.com for permission.
Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
author nor the publisher accepts any liability for any direct,
indirect, or consequential loss or damage arising from use of, or
reliance on, this information.
===========================================================================
Multiple Vendor X Server fonts.dir File Parsing Integer Overflow
Vulnerability
iDefense Security Advisory 04.03.07
http://labs.idefense.com/intelligence/vulnerabilities/
Apr 03, 2007
I. BACKGROUND
The X Window System (or X11) is a graphical windowing system used on
Unix-like systems. It is based on a client/server model. More
information about about The X Window system is available at the
following URL.
http://en.wikipedia.org/wiki/X_Window_System
II. DESCRIPTION
Local exploitation of an integer overflow vulnerability in multiple
vendors' implementations of the X Window System font information file
parsing component could allow execution of arbitrary commands with
elevated privileges.
The vulnerability specifically exists in the parsing of the "fonts.dir"
font information file. When the element count on the first line of the
file specifies it contains more than 1,073,741,824 (2 to the power of
30) elements, a potentially exploitable heap overflow condition occurs.
III. ANALYSIS
Exploitation allows attackers to execute arbitrary code with elevated
privileges.
As the X11 server requires direct access to video hardware, it runs with
elevated privileges. A user compromising an X server would gain those
permissions.
In order to exploit this vulnerability, an attacker would need to be
able to cause the X server to use a maliciously constructed font. The
X11 server contains multiple methods for a user to define additional
paths to look for fonts. An exploit has been developed using the "-fp"
command line option to the X11 server to pass the location of the
attack to the server. It is also possible to use "xset" command with
the "fp" option to perform an attack on an already running server.
Some distributions allow users to start the X11 server only if they are
logged on at the console, while others will allow any user to start it.
Attempts at exploiting this vulnerability may put the console into an
unusable state. This will not prevent repeated exploitation attempts.
IV. DETECTION
iDefense has confirmed the existence of this vulnerability in X.Org
X11R7.1. Older versions are suspected to be vulnerable.
V. WORKAROUND
iDefense is currently unaware of any effective workaround for this
issue.
VI. VENDOR RESPONSE
The X.Org Foundation has addressed this vulnerability with source code
patches. More information can be found from their advisory at the
following URL.
http://lists.freedesktop.org/archives/xorg-announce/2007-april/0286.html
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-1352 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
security problems.
VIII. DISCLOSURE TIMELINE
02/21/2007 Initial vendor notification
02/21/2007 Initial vendor response
04/03/2007 Coordinated public disclosure
IX. CREDIT
This vulnerability was discovered by Greg MacManus of iDefense Labs.
Get paid for vulnerability research
http://labs.idefense.com/methodology/vulnerability/vcp.php
Free tools, research and upcoming events
http://labs.idefense.com/
X. LEGAL NOTICES
Copyright © 2007 iDefense, Inc.
Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
written consent of iDefense. If you wish to reprint the whole or any
part of this alert in any other medium other than electronically,
please e-mail customerservice@idefense.com for permission.
Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
author nor the publisher accepts any liability for any direct,
indirect, or consequential loss or damage arising from use of, or
reliance on, this information.
===========================================================================
Multiple Vendor X Server XC-MISC Extension Memory Corruption Vulnerability
iDefense Security Advisory 04.03.07
http://labs.idefense.com/intelligence/vulnerabilities/
Apr 03, 2007
I. BACKGROUND
The X Window System (or X11) is a graphical windowing system used on
Unix-like systems. It is based on a client/server model. More
information about about The X Window system is available at the
following URL.
http://en.wikipedia.org/wiki/X_Window_System
II. DESCRIPTION
Local exploitation of a memory corruption vulnerability in the multiple
vendor's X server implementations could allow an attacker to execute
arbitrary code with elevated privileges.
The XC-MISC extension is used by the X Server to manage resource IDs. It
is built in to the X server by default.
The vulnerability exists in the ProcXCMiscGetXIDList() function in the
XC-MISC extension. This request is used to determine what resource IDs
are available for use.
Inside this function, the ALLOCATE_LOCAL() macro is used. This macro
allocates memory on the stack or heap depending on the availability of
the alloca() function. If alloca() is available, the stack is used,
other wise the heap is used.
Due to insufficient input validation, it is possible to cause memory
corruption by passing specially crafted values to the
ProcXCMiscGetXIDList() handler function.
III. ANALYSIS
Exploitation allows attackers to execute arbitrary code with elevated
privileges.
As the X11 server requires direct access to video hardware, it runs with
elevated privileges. A user compromising an X server would gain those
permissions.
In order to exploit this vulnerability an attacker would require the
ability to send commands to an affected X server. This typically
requires access to the console, or access to the same account as a user
who is on the console. One method of gaining the required access would
be to remotely exploit a vulnerability in, for example, a graphical web
browser. This would then allow an attacker to exploit this vulnerability
and elevate their privileges to root.
Attempts at exploiting this vulnerability may put the console into an
unusable state. This will not prevent repeated exploitation attempts.
IV. DETECTION
iDefense has confirmed the existence of this vulnerability in the X.org
server version 7.1-1.1.0. Previous versions may also be affected.
V. WORKAROUND
iDefense is currently unaware of any workarounds for this issue.
VI. VENDOR RESPONSE
The X.Org Foundation has addressed this vulnerability with source code
patches. More information can be found from their advisory at the
following URL.
http://lists.freedesktop.org/archives/xorg-announce/2007-april/0286.html
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-1003 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
security problems.
VIII. DISCLOSURE TIMELINE
02/08/2007 Initial vendor notification
02/09/2007 Initial vendor response
04/03/2007 Coordinated public disclosure
IX. CREDIT
This vulnerability was discovered by Sean Larsson of iDefense Labs.
Get paid for vulnerability research
http://labs.idefense.com/methodology/vulnerability/vcp.php
Free tools, research and upcoming events
http://labs.idefense.com/
X. LEGAL NOTICES
Copyright © 2007 iDefense, Inc.
Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
written consent of iDefense. If you wish to reprint the whole or any
part of this alert in any other medium other than electronically,
please e-mail customerservice@idefense.com for permission.
Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
author nor the publisher accepts any liability for any direct,
indirect, or consequential loss or damage arising from use of, or
reliance on, this information.
- --------------------------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:
http://www.auscert.org.au/render.html?cid=1980
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:
http://www.auscert.org.au/render.html?it=3192
===========================================================================
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
iQCVAwUBRhNGVyh9+71yA2DNAQJlTAP/e+PZ7Dus3VpDpOyBXQkSu5tX8JWd0AB3
I8YmanFWXFaH3Brthc8uBVvnf/69MRT1P79le1L6+27g4PZWj+s05X9wACBS2/bx
DFgHW5T4H/JPmv0s1df6CvBGZ96aW5jfV58jhNdXCVumcLE5mI9fRXi7ysYooXgL
swKCDDmIcBk=
=NPBw
-----END PGP SIGNATURE-----