CVE-2016-3714 ImageMagick

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Background Information

On Tuesday, May 3 2016, ImageMagick announced a vulnerability in all versions of the ImageMagick software. ImageMagick is a software package commonly used by web services to process images.

Impact

One of the reported vulnerabilities can potentially be exploited for remote code execution (RCE).
Releases

ImageMagick has not released a fix, but plans to publish a new version of ImageMagic with the fixes soon.

cPanel, L.L.C. normally releases all builds at once in order to limit the ability to reverse engineer fixes. However, this vulnerability is already wildly known and we have seen reports of it’s use. In this instance, we plan to release builds as soon as they become available.

At this time, the following builds are available:

• 11.56 — 11.56.0.13
• 11.54 — 11.54.0.23
• EDGE — 11.55.9999.193
• CURRENT — 11.56.0.13
• RELEASE — 11.56.0.13
• STABLE — 11.54.0.23

How to determine if your server is up to date

The updated RPMs provided by cPanel will contain a changelog entry with a CVE number. To view this changelog entry run the following command:

rpm -q --changelog cpanel-ImageMagick | grep CVE-2016-3714

The output should resemble below:

- Apply workaround for CVE-2016-3714

What to do if you are not up-to-date

If your server is not running one of the above versions, update immediately.

To upgrade your server, navigate to WHM’s Upgrade to Latest Version interface (WHM >> Home >> cPanel >> Upgrade to Latest Version) and click Click to Upgrade.

To upgrade cPanel from the command line run the following commands:

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/scripts/upcp
/scripts/check_cpanel_rpms --fix --long-list

To verify the new cpanel-ImageMagick RPM was installed run the following command:

rpm -q --changelog cpanel-ImageMagick | grep CVE-2016-3714

The output should resemble the following:

- Apply workaround for CVE-2016-3714

Manual mitigation

We will publish builds for 11.52, and 11.50 as soon as they become available. We will attempt use WHM’s Autofixer to update the policy.xml file. For 11.52, and 11.50, you can manually mitigate this vulnerability with the following instructions.

1. Open the following file:

   /usr/local/cpanel/3rdparty/etc/ImageMagick-6/policy.xml

2. Update the file to match the policy example below to disable the EPHEMERAL, URL, HTTPS, MVG, and MSL coders.

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   <policymap> <policy domain="coder" rights="none" pattern="EPHEMERAL" /> <policy domain="coder" rights="none" pattern="URL" /> <policy domain="coder" rights="none" pattern="HTTPS" /> <policy domain="coder" rights="none" pattern="MVG" /> <policy domain="coder" rights="none" pattern="MSL" /> </policymap>

How to mitigate the vulnerability for other ImageMagick installations

If you have a local installation of ImageMagick, we recommend that you use a policy file to disable the vulnerable ImageMagick coders. The global policy for ImageMagick is usually found in the /etc/ImageMagick/policy.xml file. The following policy.xml example disables the coders EPHEMERAL, URL, HTTPS, MVG, and MSL:

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<policymap>
<policy domain="coder" rights="none" pattern="EPHEMERAL" />
<policy domain="coder" rights="none" pattern="URL" />
<policy domain="coder" rights="none" pattern="HTTPS" />
<policy domain="coder" rights="none" pattern="MVG" />
<policy domain="coder" rights="none" pattern="MSL" />
</policymap>

If you are still experiencing issues or need additional help, contact cPanel support.