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CVE-2017-10917: Xen: Information disclosure

CVE-2017-10917 is rated critical with a CVSS v3.0 base score of 9.1 and affects Xen. Per its scoring, it can be exploited over the network, without authentication, without any user interaction.

Vulnerability description

Xen through 4.8.x does not validate the port numbers of polled event channel ports, which allows guest OS users to cause a denial of service (NULL pointer dereference and host OS crash) or possibly obtain sensitive information, aka XSA-221.

Severity breakdown

CVSS v3.0 9.1: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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: Unchanged. Impact stays within the vulnerable component.
• Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
• Integrity impact: None. No loss of integrity.
• Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-476: NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.

Affected products

• Xen: up to and including 4.8.1

References

• https://xenbits.xen.org/xsa/advisory-221.html
• http://www.debian.org/security/2017/dsa-3969
• http://www.securityfocus.com/bid/99157
• http://www.securitytracker.com/id/1038731
• https://security.gentoo.org/glsa/201708-03