CVE-2020-15564

medium
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Description

An issue was discovered in Xen through 4.13.x, allowing Arm guest OS users to cause a hypervisor crash because of a missing alignment check in VCPUOP_register_vcpu_info. The hypercall VCPUOP_register_vcpu_info is used by a guest to register a shared region with the hypervisor. The region will be mapped into Xen address space so it can be directly accessed. On Arm, the region is accessed with instructions that require a specific alignment. Unfortunately, there is no check that the address provided by the guest will be correctly aligned. As a result, a malicious guest could cause a hypervisor crash by passing a misaligned address. A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS). All Xen versions are vulnerable. Only Arm systems are vulnerable. x86 systems are not affected.

References

http://xenbits.xen.org/xsa/advisory-327.html

http://www.openwall.com/lists/oss-security/2020/07/07/5

https://www.debian.org/security/2020/dsa-4723

https://lists.fedoraproject.org/archives/list/[email protected]/message/VB3QJJZV23Z2IDYEMIHELWYSQBUEW6JP/

https://lists.fedoraproject.org/archives/list/[email protected]/message/MXESCOVI7AVRNC7HEAMFM7PMEO6D3AUH/

https://security.gentoo.org/glsa/202007-02

Details

Source: MITRE

Published: 2020-07-07

Updated: 2021-07-21

Type: CWE-20

Risk Information

CVSS v2

Base Score: 4.9

Vector: AV:L/AC:L/Au:N/C:N/I:N/A:C

Impact Score: 6.9

Exploitability Score: 3.9

Severity: MEDIUM

CVSS v3

Base Score: 6.5

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Impact Score: 4

Exploitability Score: 2

Severity: MEDIUM

Vulnerable Software

Configuration 1

OR

cpe:2.3:o:xen:xen:*:*:*:*:*:*:arm:* versions from 4.8.0 to 4.13.1 (inclusive)

Configuration 2

OR

cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

Tenable Plugins

View all (5 total)

IDNameProductFamilySeverity
149066Xen Missing Alignment Check DoS (XSA-327)NessusMisc.
medium
138925GLSA-202007-02 : Xen: Multiple vulnerabilitiesNessusGentoo Local Security Checks
high
138864Fedora 31 : xen (2020-76cf2b0f0a)NessusFedora Local Security Checks
high
138535Fedora 32 : xen (2020-fbc13516af)NessusFedora Local Security Checks
high
138394Debian DSA-4723-1 : xen - security updateNessusDebian Local Security Checks
high