Citrix Security Advisory for TCP/IP Reassembly Resource Exhaustion

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<h2> Description of Problem</h2>
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<p>Several vulnerabilities in TCP/IP reassembly commonly known as SegmentSmack and FragmentSmack have recently been disclosed. SegmentSmack is CVE-2018-5390 for Linux and CVE-2018-6922 for FreeBSD. FragmentSmack is CVE-2018-5391 for Linux and CVE-2018-6923 for FreeBSD. These vulnerabilities could potentially allow an attacker that has the ability to maintain a TCP or IP stream with a vulnerable component to send crafted packets that cause high CPU usage or CPU resource exhaustion leading to denial of service.</p>
<p>Vulnerable reassembly is provided by some Linux-based or FreeBSD-based operating systems. Customers managing Linux or FreeBSD platforms on which Citrix components are deployed are advised to apply any appropriate operating system updates.</p>
<p>The following sections provide guidance on the impact and mitigation steps for Linux-based and FreeBSD-based Citrix products. Citrix products that do not include or execute on these platforms are not impacted by this vulnerability.</p>
<p>Windows-based components of XenDesktop and XenApp are not impacted by this issue.</p>
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<h2> What Citrix Is Doing</h2>
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<p>Citrix is in the process of analyzing the potential impact of this issue on currently supported products. </p>
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<h2> Product Details</h2>
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<h2> ByteMobile ATM</h2>
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<p>ByteMobile ATM is affected by CVE-2018-5390 & CVE-2018-5391 and has been addresed in version 8.2.4.1. </p>
<p>Please contact support to access the updated version. More information on the 8.2.4.1 release can be found at the following location <a href=“https://support.citrix.com/article/CTX228251”>https://support.citrix.com/article/CTX228251</a></p>
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<h2> Citrix NetScaler</h2>
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<p>NetScaler MPX and NetScaler VPX are not impacted by CVE-2018-5390, CVE-2018-6922, CVE-2018-5391 and CVE-2018-6923</p>
<p>NetScaler SVM and NetScaler MAS are not impacted by CVE-2018-5390 & CVE-2018-5391</p>
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<h2> Citrix XenServer</h2>
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<p>Analysis of the impact of this issue on Citrix XenServer is in progress. This section will be updated as soon as additional information is available.</p>
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<h2> Citrix XenMobile</h2>
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<p>Analysis of the impact of this issue on Citrix XenMobile is in progress. This section will be updated as soon as additional information is available.</p>
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<h2> Citrix Receiver for Linux</h2>
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<p>Citrix recommends that customers apply any applicable patches to the underlying Linux operating system.</p>
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<h2> Citrix Linux Virtual Desktop</h2>
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<p>Citrix Linux Virtual Desktop deployments may be impacted by this operating system vulnerability. Citrix recommends that customers apply any applicable patches to the underlying Linux operating system.</p>
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<h2> Citrix Licensing</h2>
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<p>Analysis of the impact of this issue on Citrix Licensing is in progress. This section will be updated as soon as additional information is available.</p>
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<h2> Citrix XenDesktop Volume Worker Template</h2>
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<p>Amazon Web Services based deployments use the Linux AMI template. Guidance from Amazon about this issue can be found at the following location: <a></a><a href=“https://aws.amazon.com/security/security-bulletins/AWS-2018-018/”>https://aws.amazon.com/security/security-bulletins/AWS-2018-018/</a></p>
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<p>The above list will be updated as the analysis into this issue progresses.</p>
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<h2> Obtaining Support on This Issue</h2>
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<p>If you require technical assistance with this issue, please contact Citrix Technical Support. Contact details for Citrix Technical Support are available at <u> <a href=“https://www.citrix.com/support/open-a-support-case.html”>https://www.citrix.com/support/open-a-support-case.html</a></u>. </p>
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<h2> Reporting Security Vulnerabilities</h2>
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<p>Citrix welcomes input regarding the security of its products and considers any and all potential vulnerabilities seriously. For guidance on how to report security-related issues to Citrix, please see the following document: CTX081743 – <a href=“http://support.citrix.com/article/CTX081743”>Reporting Security Issues to Citrix</a></p>
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<h2> Changelog</h2>
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<td colspan=“1” rowspan=“1”>Date </td>
<td colspan=“1” rowspan=“1”>Change</td>
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<td colspan=“1” rowspan=“1”>August 8th 2018</td>
<td colspan=“1” rowspan=“1”>Initial bulletin published</td>
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<td colspan=“1” rowspan=“1”>August 16th 2018</td>
<td colspan=“1” rowspan=“1”>Added CVE-2018-5391 and CVE-2018-6923 details</td>
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<td colspan=“1” rowspan=“1”>November 13th 2018</td>
<td colspan=“1” rowspan=“1”>Added ByteMobile ATM </td>
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