CVE-2020-29479 Information

Description

An issue was discovered in Xen through 4.14.x. In the Ocaml xenstored implementation the internal representation of the tree has special cases for the root node because this node has no parent. Unfortunately permissions were not checked for certain operations on the root node. Unprivileged guests can get and modify permissions list and delete the root node. (Deleting the whole xenstore tree is a host-wide denial of service.) Achieving xenstore write access is also possible. All systems using oxenstored are vulnerable. Building and using oxenstored is the default in the upstream Xen distribution if the Ocaml compiler is available. Systems using C xenstored are not vulnerable.

CVSS Vector

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

Reference

https://xenbits.xenproject.org/xsa/advisory-353.html https://www.debian.org/security/2020/dsa-4812 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OBLV6L6Q24PPQ2CRFXDX4Q76KU776GKI/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2C6M6S3CIMEBACH6O7V4H2VDANMO6TVA/ https://security.gentoo.org/glsa/202107-30

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

CHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

8.8