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CVE-2017-10918: Xen: Improper Input Validation

CVE-2017-10918 is rated critical with a CVSS v3.0 base score of 10.0 and affects Xen. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.

Vulnerability description

Xen through 4.8.x does not validate memory allocations during certain P2M operations, which allows guest OS users to obtain privileged host OS access, aka XSA-222.

Severity breakdown

CVSS v3.0 10.0: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

• Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
• Attack complexity: Low. No special conditions; the attack can be repeated reliably.
• Privileges required: None. No account or prior access is needed.
• User interaction: None. No action from any user is needed.
• Scope: Changed. Impact reaches beyond the vulnerable component to other resources.
• Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
• Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
• Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-20: Improper Input Validation

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.

Affected products

• Xen: up to and including 4.8.1

References

• https://xenbits.xen.org/xsa/advisory-222.html
• http://www.securityfocus.com/bid/99161
• http://www.debian.org/security/2017/dsa-3969
• http://www.securitytracker.com/id/1038732
• https://security.gentoo.org/glsa/201708-03
• https://security.gentoo.org/glsa/201710-17