CVE-2021-28507

Public Exploit
An issue has recently been discovered in Arista EOS where, under certain conditions, the service ACL configured for OpenConfig gNOI and OpenConfig RESTCONF might be bypassed, which results in the denied requests being forwarded to the agent.

Description

An issue has recently been discovered in Arista EOS where, under certain conditions, the service ACL configured for OpenConfig gNOI and OpenConfig RESTCONF might be bypassed, which results in the denied requests being forwarded to the agent.

Remediation

Solution:

  • The recommended resolution is to upgrade to a remediated software version at your earliest convenience. Arista recommends customers move to the latest version of each release. CVE-2021-28507 has been fixed in the following releases: 4.26.3M and later releases in the 4.26.x train 4.25.6M and later releases in the 4.25.x train 4.25.4.1M and later releases in the 4.25.4.x train 4.24.8M and later releases in the 4.24.x train 4.23.10M and later releases in the 4.23.x train

Workaround:

  • On the affected versions, all vulnerabilities can be mitigated by disabling OpenConfig gNMI/gNOI and OpenConfig RESTCONF and TerminAttr. If use of these agents is required, a hotfix employing a proxy service can be deployed.
  • To mitigate CVE-2021-28507 with the continued use of the affected agents, a hotfix employing a proxy service can be deployed. The proxy is configured behind the gNMI/gNOI or RESTCONF server. The hotfix can be downloaded at https://www.arista.com/en/support/advisories-notices/sa-download/?sa=71-SecurityAdvisory0071Hotfix.i386.swix for 32 bit systems and https://www.arista.com/en/support/advisories-notices/sa-download/?sa=71-SecurityAdvisory0071Hotfix.x86_64.swix for 64 bit systems.

Category

5.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.10%
Vendor Advisory arista.com
Affected: Arista Networks EOS
Published at:
Updated at:

References

Link Tags
https://www.arista.com/en/support/advisories-notices/security-advisories/13449-security-advisory-0071 patch vendor advisory mitigation exploit

Frequently Asked Questions

What is the severity of CVE-2021-28507?
CVE-2021-28507 has been scored as a medium severity vulnerability.
How to fix CVE-2021-28507?
To fix CVE-2021-28507: The recommended resolution is to upgrade to a remediated software version at your earliest convenience. Arista recommends customers move to the latest version of each release. CVE-2021-28507 has been fixed in the following releases: 4.26.3M and later releases in the 4.26.x train 4.25.6M and later releases in the 4.25.x train 4.25.4.1M and later releases in the 4.25.4.x train 4.24.8M and later releases in the 4.24.x train 4.23.10M and later releases in the 4.23.x train
Is CVE-2021-28507 being actively exploited in the wild?
It is possible that CVE-2021-28507 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-28507?
CVE-2021-28507 affects Arista Networks EOS.
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