CVE-2020-29487

Published: Dic 15, 2020 Last Modified: Nov 21, 2024 EU-VD ID: EUVD-2020-21855 Aliases: GSD-2020-29487
ExploitDB:
Other exploit source:
Google Dorks:
HIGH 7,5
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Scope: unchanged
Confidentiality: none
Integrity: none
Availability: high
HIGH 7,8
Source: [email protected]
Access Vector: network
Access Complexity: low
Authentication: none
Confidentiality: none
Integrity: none
Availability: complete

Description

AI Translation Available

An issue was discovered in Xen XAPI before 2020-12-15. Certain xenstore keys provide feedback from the guest, and are therefore watched by toolstack. Specifically, keys are watched by xenopsd, and data are forwarded via RPC through message-switch to xapi. The watching logic in xenopsd sends one RPC update containing all data, any time any single xenstore key is updated, and therefore has O(N^2) time complexity. Furthermore, message-switch retains recent (currently 128) RPC messages for diagnostic purposes, yielding O(M*N) space complexity. The quantity of memory a single guest can monopolise is bounded by xenstored quota, but the quota is fairly large. It is believed to be in excess of 1G per malicious guest. In practice, this manifests as a host denial of service, either through message-switch thrashing against swap, or OOMing entirely, depending on dom0's configuration. (There are no quotas in xenopsd to limit the quantity of keys that result in RPC traffic.) A buggy or malicious guest can cause unreasonable memory usage in dom0, resulting in a host denial of service. All versions of XAPI are vulnerable. Systems that are not using the XAPI toolstack are not vulnerable.

EPSS (Exploit Prediction Scoring System)

Trend Analysis

EPSS (Exploit Prediction Scoring System)

Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.

EPSS Score
0,0037
Percentile
0,6th
Updated

EPSS Score Trend (Last 90 Days)

770

Allocation of Resources Without Limits or Throttling

Incomplete
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Availability
Potential Impacts:
Dos: Resource Consumption (Cpu) Dos: Resource Consumption (Memory) Dos: Resource Consumption (Other)
Applicable Platforms
All platforms may be affected
Likelihood of Exploit: High
View CWE Details
Operating System

Xapi by Xen

Product Information
Vendor Xen
Product Xapi
Version Range Affected
To 2020-12-15 (exclusive)
cpe:2.3:o:xen:xapi:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
https://security.gentoo.org/glsa/202107-30
Third Party Advisory
https://security.gentoo.org/glsa/202107-30
https://xenbits.xenproject.org/xsa/advisory-354.html
Patch Vendor Advisory
https://xenbits.xenproject.org/xsa/advisory-354.html
https://security.gentoo.org/glsa/202107-30
Third Party Advisory
https://security.gentoo.org/glsa/202107-30
https://xenbits.xenproject.org/xsa/advisory-354.html
Patch Vendor Advisory
https://xenbits.xenproject.org/xsa/advisory-354.html