Quantum Secular Labs / Blog / Advisories

CVE-2017-16845: Qemu: Improper Input Validation

CVE-2017-16845 is rated critical with a CVSS v3.1 base score of 10.0 and affects Qemu, along with 2 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction.

Vulnerability description

hw/input/ps2.c in Qemu does not validate 'rptr' and 'count' values during guest migration, leading to out-of-bounds access.

Severity breakdown

CVSS v3.1 10.0: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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: 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: None. No loss of integrity.
• 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

• Qemu: up to and including 2.11.2
• Debian Linux: 8.0; 9.0
• Canonical Ubuntu Linux: 14.04; 16.04; 17.10; 18.04

References

• https://lists.gnu.org/archive/html/qemu-devel/2017-11/msg02982.html
• http://www.securityfocus.com/bid/101923
• https://lists.debian.org/debian-lts-announce/2018/09/msg00007.html
• https://usn.ubuntu.com/3575-1/
• https://usn.ubuntu.com/3649-1/
• https://www.debian.org/security/2018/dsa-4213