CVE-2020-29487
Xen XAPI Denial of Service Vulnerability
Description
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.
INFO
Published Date :
Dec. 15, 2020, 6:15 p.m.
Last Modified :
Nov. 21, 2024, 5:24 a.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
3.6
Exploitability Score :
3.9
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2020-29487.
| URL | Resource |
|---|---|
| https://security.gentoo.org/glsa/202107-30 | Third Party Advisory |
| https://xenbits.xenproject.org/xsa/advisory-354.html | Patch Vendor Advisory |
| https://security.gentoo.org/glsa/202107-30 | Third Party Advisory |
| https://xenbits.xenproject.org/xsa/advisory-354.html | Patch Vendor Advisory |
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2020-29487 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2020-29487 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference https://security.gentoo.org/glsa/202107-30 Added Reference https://xenbits.xenproject.org/xsa/advisory-354.html -
CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
Modified Analysis by [email protected]
Dec. 10, 2021
Action Type Old Value New Value Changed Reference Type https://security.gentoo.org/glsa/202107-30 No Types Assigned https://security.gentoo.org/glsa/202107-30 Third Party Advisory -
CVE Modified by [email protected]
Jul. 12, 2021
Action Type Old Value New Value Added Reference https://security.gentoo.org/glsa/202107-30 [No Types Assigned] -
Initial Analysis by [email protected]
Dec. 22, 2020
Action Type Old Value New Value Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:N/I:N/A:C) Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Changed Reference Type https://xenbits.xenproject.org/xsa/advisory-354.html No Types Assigned https://xenbits.xenproject.org/xsa/advisory-354.html Patch, Vendor Advisory Added CWE NIST CWE-770 Added CPE Configuration OR *cpe:2.3:o:xen:xapi:*:*:*:*:*:*:*:* versions up to (excluding) 2020-12-15
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2020-29487 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2020-29487
weaknesses.
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
0.10 }} 0.01%
score
0.42455
percentile