CVE-2020-29479

Severity Score

8.8

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

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.

Se detectó un problema en Xen versiones hasta 4.14.x. En la implementación de Ocaml xenstored, la representación interna del árbol tiene casos especiales para el nodo root, porque este nodo no tiene padre. Desafortunadamente, no fueron comprobados los permisos para determinadas operaciones en el nodo root. Los invitados no privilegiados pueden obtener y modificar permisos, enumerar y eliminar el nodo root. (Eliminar todo el árbol de xenstore es una denegación de servicio en todo el host). Lograr el acceso de escritura a xenstore también es posible. Todos los sistemas que usan oxenstored son vulnerables. La construcción y el uso de oxenstored es el valor predeterminado en la distribución Xen previa, si el compilador Ocaml está disponible. Los sistemas que utilizan C xenstored no son vulnerables

*Credits: N/A

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Local

Attack Complexity

Low

Authentication

None

Confidentiality

Complete

Integrity

Complete

Availability

Complete

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-12-03 CVE Reserved
2020-12-15 CVE Published
2023-03-08 EPSS Updated
2024-08-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-862: Missing Authorization

CAPEC

References (5)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC
https://xenbits.xenproject.org/xsa/advisory-353.html	2023-11-07

URL	Date	SRC
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2C6M6S3CIMEBACH6O7V4H2VDANMO6TVA	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OBLV6L6Q24PPQ2CRFXDX4Q76KU776GKI	2023-11-07
https://security.gentoo.org/glsa/202107-30	2023-11-07
https://www.debian.org/security/2020/dsa-4812	2023-11-07

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Xen Search vendor "Xen"		Xen Search vendor "Xen" for product "Xen"				<= 4.14.0 Search vendor "Xen" for product "Xen" and version " <= 4.14.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				10.0 Search vendor "Debian" for product "Debian Linux" and version "10.0"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				32 Search vendor "Fedoraproject" for product "Fedora" and version "32"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				33 Search vendor "Fedoraproject" for product "Fedora" and version "33"		-		Affected