Xen up to 4.12.x Pagetable HVM Guest input validation

Summaryinfo

A vulnerability has been found in Xen up to 4.12.x and classified as critical. Affected is an unknown function of the component Pagetable Handler. Performing a manipulation as part of HVM Guest results in input validation. This vulnerability was named CVE-2019-19577. The attack may be carried out on the physical device. There is no available exploit.

Detailsinfo

A vulnerability was found in Xen up to 4.12.x (Virtualization Software). It has been classified as critical. This affects an unknown part of the component Pagetable Handler. The manipulation as part of a HVM Guest leads to a input validation vulnerability. CWE is classifying the issue as CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

An issue was discovered in Xen through 4.12.x allowing x86 AMD HVM guest OS users to cause a denial of service or possibly gain privileges by triggering data-structure access during pagetable-height updates. When running on AMD systems with an IOMMU, Xen attempted to dynamically adapt the number of levels of pagetables (the pagetable height) in the IOMMU according to the guest's address space size. The code to select and update the height had several bugs. Notably, the update was done without taking a lock which is necessary for safe operation. A malicious guest administrator can cause Xen to access data structures while they are being modified, causing Xen to crash. Privilege escalation is thought to be very difficult but cannot be ruled out. Additionally, there is a potential memory leak of 4kb per guest boot, under memory pressure. Only Xen on AMD CPUs is vulnerable. Xen running on Intel CPUs is not vulnerable. ARM systems are not vulnerable. Only systems where guests are given direct access to physical devices are vulnerable. Systems which do not use PCI pass-through are not vulnerable. Only HVM guests can exploit the vulnerability. PV and PVH guests cannot. All versions of Xen with IOMMU support are vulnerable.

The weakness was presented 12/11/2019. This vulnerability is uniquely identified as CVE-2019-19577 since 12/04/2019. The exploitability is told to be easy. Attacking locally is a requirement. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

See VDB-147007, VDB-147006, VDB-147005 and VDB-147004 for similar entries. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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
• 4.9
• 4.10
• 4.11
• 4.12

License

• open-source

CPE 2.3info

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CPE 2.2info

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Entryinfo

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