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ESX Server 3.0.0 Patch ESX-2533126: AMD fxsave/fxrstor Security Vulnerability

Details

Security Issues

This patch closes the security hole for AMD processors used with ESX 3.0.0, preventing attackers from monitoring the FPU execution path.
 
The instructions fxsave and fxrstor on AMD CPUs are used to save or restore the FPU registers (FOP, FIP, and FDP). On AMD Opteron processors, these instructions do not save/restore some exception-related registers unless an exception is currently being serviced. This can lead to a security hole that allows local attackers to monitor the execution path of FPU processes, possibly allowing them to obtain sensitive information being passed through those processes.
 
The CVE (Common Vulnerabilities and Exposures) entry for this issue is CVE-2006-1056.
 
Note: This vulnerability exists for all AMD Athlon, Duron, Athlon MP, Athlon XP, Athlon64, Athlon64 FX, Opteron, Turion, and Sempron processors, but AMD Opteron processors are the only AMD processors supported with ESX Server.

 

Solution

Applicability

This patch is for ESX Server 3.0.0 only. This patch does not apply to ESX Server versions 3.0.1 and higher. The vulnerability has already been addressed in later versions of ESX Server.

Installing the Patch

Download Instructions

Note: By default, the ESX Server host will reboot after the patch is applied.

Download and verify the patch bundle as follows:

  2. Log into the ESX Server service console as root.
  3. Create a local depot directory.

    # mkdir /var/updates

    Note: VMware recommends that you use the updates directory.

  4. Change your working directory to /var/updates.

    # cd /var/updates

  5. Download the tar file into the /var/updates directory.
  6. Verify the integrity of the downloaded tar file.

    # md5sum ESX-2533126.tgz

  7. The md5 checksum output should match the following:

    f34bd684a50a29d667bd0ea5c8c8ef63 ESX-2533126.tgz

  8. Extract the compressed tar archive.

    # tar -xvzf ESX-2533126.tgz

  9. Change to the newly created directory, /var/updates/ESX-2533126.

    # cd ESX-2533126

Installation Instructions

After you have downloaded and extracted the archive, and if you are in the directory you created above, install the update using the following command:

# esxupdate update

If you want to run esxupdate from a different directory, you must specify the bundle path in the command:

# esxupdate -r file:<directory>/ESX-2533126 update

For example, if the host is called depot:

# esxupdate –r file:///depot/var/updates/ESX-2533126 update

During the update process, logs appear on the terminal. You can specify the verbosity of esxupdate logs by using the -v option as shown below:

# esxupdate -v 10 -r file:<directory>/ESX-2533126 update

For more information on using esxupdate, please refer to the Patch Management for ESX Server 3 tech note at http://www.vmware.com/pdf/esx3_esxupdate.pdf.

Acknowledgement

The VMware Security team would like to thank AMD, Richard Brunner, and the FreeBSD security team for their parts in resolving this issue. 

Keywords

esx300;esxpatch alertz; urlz

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Actions
  • KB Article: 2533126
  • Updated: Aug 14, 2009
  • Products:
    VMware ESX
  • Product Versions:
    VMware ESX 3.0.x