Xen up to 4.8.x grant-table access control

Summaryinfo

A vulnerability was found in Xen up to 4.8.x. It has been classified as critical. This affects an unknown function of the component grant-table. This manipulation causes access control. This vulnerability is registered as CVE-2017-10920. Remote exploitation of the attack is possible. No exploit is available. Applying a patch is the recommended action to fix this issue.

Detailsinfo

A vulnerability has been found in Xen up to 4.8.x (Virtualization Software) and classified as critical. Affected by this vulnerability is an unknown code block of the component grant-table. The manipulation with an unknown input leads to a access control vulnerability. The CWE definition for the vulnerability is CWE-264. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

The grant-table feature in Xen through 4.8.x mishandles a GNTMAP_device_map and GNTMAP_host_map mapping, when followed by only a GNTMAP_host_map unmapping, which allows guest OS users to cause a denial of service (count mismanagement and memory corruption) or obtain privileged host OS access, aka XSA-224 bug 1.

The bug was discovered 06/20/2017. The weakness was published 07/05/2017 as XSA-224 as confirmed security advisory (Website). The advisory is shared at xenbits.xen.org. This vulnerability is known as CVE-2017-10920 since 07/04/2017. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1068 for this issue.

The vulnerability was handled as a non-public zero-day exploit for at least 14 days. During that time the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 101638 (Fedora 26 : xen (2017-5c6a9b07a3)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Fedora Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 276751 (Fedora Security Update for xen (FEDORA-2017-c3149b5fcb)).

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (101638). Similar entries are available at VDB-103037, VDB-103038, VDB-103039 and VDB-103040. If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Virtualization Software

Name

• Xen

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8

License

• open-source

CPE 2.3info

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CPE 2.2info

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Entryinfo

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