Description
This advisory documents the impact of an internally found vulnerability in Arista EOS for security ACL bypass. The impact of this vulnerability is that the security ACL drop rule might be bypassed if a NAT ACL rule filter with permit action matches the packet flow. This could allow a host with an IP address in a range that matches the range allowed by a NAT ACL and a range denied by a Security ACL to be forwarded incorrectly as it should have been denied by the Security ACL. This can enable an ACL bypass.
Published: 2022-08-05
Score: 5.8 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

No analysis available yet.

Remediation

Vendor Solution

The recommended resolution is to upgrade to a remediated software version at your earliest convenience. The fixed versions for the currently supported release trains are as follows: 4.24.10 and later releases in the 4.24.x train 4.25.9 and later releases in the 4.25.x train 4.26.6 and later releases in the 4.26.x train 4.27.4 and later releases in the 4.27.x train 4.28.0 and later releases in the 4.28.x train


Vendor Workaround

Configure a NAT “drop” ACL rule for each security ACL “drop” rule that should be applied to the interface that has NAT configured. This will prevent the packets from being translated at the expense of maintaining the configuration in two places.

Tracking

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Advisories
Source ID Title
EUVD EUVD EUVD-2021-15187 This advisory documents the impact of an internally found vulnerability in Arista EOS for security ACL bypass. The impact of this vulnerability is that the security ACL drop rule might be bypassed if a NAT ACL rule filter with permit action matches the packet flow. This could allow a host with an IP address in a range that matches the range allowed by a NAT ACL and a range denied by a Security ACL to be forwarded incorrectly as it should have been denied by the Security ACL. This can enable an ACL bypass.
History

No history.

Subscriptions

Arista 7050cx3-32s 7050cx3m-32s 7050sx3-48c8 7050sx3-48yc 7050sx3-48yc12 7050sx3-48yc8 7050sx3-96yc8 7050tx3-48c8 720xp-24y6 720xp-24zy4 720xp-48y6 720xp-48zc2 720xp-96zc2 7300x3-32c 7300x3-48yc4 Eos
cve-icon MITRE

Status: PUBLISHED

Assigner: Arista

Published:

Updated: 2024-09-16T17:15:30.137Z

Reserved: 2021-03-16T00:00:00.000Z

Link: CVE-2021-28511

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2022-08-05T17:15:07.957

Modified: 2024-11-21T05:59:48.747

Link: CVE-2021-28511

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses