Note: This is an archival copy of Security Sun Alert 238686 as previously published on http://sunsolve.sun.com.|
Latest version of this security advisory is available from http://support.oracle.com as Sun Alert 1019343.1.
Solaris 8 Operating System
Solaris 9 Operating System
Solaris 10 Operating System
Date of Workaround Release
Date of Resolved Release
Multiple Security Vulnerabilities in the Solaris X Server Extensions May Lead to a Denial of Service (DoS) Condition or Allow Execution of Arbitrary Code
Multiple integer, heap and buffer overflow security vulnerabilities exist in the Render, RECORD, Security, and MIT-SHM Extensions to the Solaris X11 display server (Xorg(1) and Xsun(1)) and the Solaris X11 print server (Xprt(1)). These vulnerabilities may allow a local or remote unprivileged user who is authorized (via xhost(1) or xauth(1)) to connect to the X server and execute arbitrary code with root privileges, access arbitrary memory within the X server's address space, or crash the X11 display server process. The ability to crash the X11 display server is a type of Denial of Service (DoS).
These issues are described in the following documents:
CVE-2008-2360 at http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-2360
CVE-2008-2361 at http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-2361
CVE-2008-2362 at http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-2362
CVE-2008-1379 at http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-1379
CVE-2008-1377 at http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-1377
2. Contributing Factors
These issues can occur in the following releases:
1. To determine if JDS release 2 is installed on a Solaris 9 x86 system, the following command can be run:
% grep distributor-version /usr/share/gnome-about/gnome-version.xml2. Only OpenSolaris installations including the affected binary "/usr/X11/bin/i386/Xorg" are impacted by this issue.
3. OpenSolaris distributions may include additional bug fixes above and beyond the base build from which it was derived. The base build can be derived as follows:
$ uname -a4. To determine if the affected X Server extensions are enabled on a running X server, the following command can be run:
$ xdpyinfo | egrep "MIT-SHM|RENDER|SECURITY|RECORD"On Solaris 10, in the case of Xsun(1), the issues reported in CVE-2008-2360, CVE-2008-2361 and CVE-2008-2362 will not be applicable by default. They will be applicable only if the user has turned on the RENDER extension support by adding "+xrender" CLI option to Xsun, in which case the user can work around it by removing the "+xrender" option. Also, these issues are not applicable for Xsun(1) server on Solaris 8 as the RENDER extension support is not present.
There are no predictable symptoms that would indicate these issues have been exploited to execute arbitrary code.
If any of the described issues do occur, the X server will exit and may generate an error message about a segmentation fault and may also write a core(4) file.
To work around the described issues for the Xorg(1) server, the affected X Server extensions may be disabled.
The following command may be used to disable Xorg server extensions:
$ /usr/X11/bin/Xorg -extension <Name of Extension>This change will be valid until the Xorg server is restarted, for example on logout. The command will need to be repeated for each new instance of the Xorg server.
For example, the MIT-SHM extension may be disabled as follows:
$ /usr/X11/bin/Xorg -extension MIT-SHMThe X Server extensions may also be disabled by editing the xorg.conf(4) file. For example, to disable the MIT-SHM extension, the following lines may be added to the xorg.conf(4) file:
Option "MIT-SHM" "disable"
Option "RENDER" "disable"
Option "SECURITY" "disable"
1. After disabling X Server extensions, applications requiring those extensions may not run.
2. Only certain extensions can be disabled by the user. To list all extensions that can be disabled, the following command can be run:
$ /usr/X11/bin/Xorg -extension helpFor Xsun(1) server, there is no workaround to the issues described in CVE-2008-1377 and CVE-2008-1379.
To work around the issues for Xsun(1) server with Render support enabled on Solaris 10 (reported in CVE-2008-2360, CVE-2008-2361 and CVE-2008-2362) remove the "+xrender" option to Xsun.
On Solaris 9, there is no workaround for the issues reported in CVE-2008-2360, CVE-2008-2361 and CVE-2008-2362 for Xsun(1) server.
The documented issues can be worked around by using the "noexec_user_stack" options to defeat the most common form of buffer overflow attacks that store executable exploit code on the stack. This can be achieved by editing the "/etc/system" file and adding the lines:
set noexec_user_stack = 1
set noexec_user_stack_log = 1
A reboot will be necessary in order for the above change to take effect. See system(4) for information on modifying the system configuration information file.
This issue is addressed in the following releases:
For more information on Security Sun Alerts, see 1009886.1.
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19-Jun-2008: Updated Contributing Factors, Workaround and Resolution sections
07-Jul-2008: Updated Contributing Factors and Resolution sections
29-Jul-2008: Updated Contributing Factors and Resolution sections
04-Aug-2008: Updated Contributing Factors and Resolution sections
24-Sep-2008: Updated Contributing Factors and Resolution sections
30-Sep-2008: Revised Workaround section; issue is Resolved
20-Jan-2009: Updated Contributing Factors and Resolution sections
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