Allocation of Resources Without Limits or Throttling in Xen

1) Allocation of Resources Without Limits or Throttling

EUVDB-ID: #VU49136

Risk: Low

CVSSv4.0: 1.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:H/E:U/U:Clear]

CVE-ID: CVE-2020-29486

CWE-ID: CWE-770 - Allocation of Resources Without Limits or Throttling

Exploit availability: No

Description

The vulnerability allows a local privileged user to a crash the entire system.

An issue was discovered in Xen through 4.14.x. Nodes in xenstore have an ownership. In oxenstored, a owner could give a node away. However, node ownership has quota implications. Any guest can run another guest out of quota, or create an unbounded number of nodes owned by dom0, thus running xenstored out of memory A malicious guest administrator can cause a denial of service against a specific guest or against the whole host. 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.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Xen: 4.0.0 - 4.14.1

CPE2.3

• cpe:2.3:a:xen_project:xen:4.0.0:*:*:*:*:*:*:*
• cpe:2.3:a:xen_project:xen:4.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:xen_project:xen:4.0.2:*:*:*:*:*:*:*

External links

https://www.debian.org/security/2020/dsa-4812
https://xenbits.xenproject.org/xsa/advisory-352.html

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.