QID 317249

Date Published: 2022-11-09

QID 317249: Cisco Nexus Operating System (NX-OS) Software Switches Bypass Configured First-hop Security (FHS) Vulnerability (cisco-sa-VU855201-J3z8CKTX)

By default, Cisco NX-OS Software processes an inbound packet with the frame header containing a VLAN ID 0 tag. The initial VLAN ID 0 tag is stripped and then processed in accordance with the rest of the packet contents. Cisco products have a limit on how many tags can be inspected to establish the upper-layer protocols.

The affected Cisco NX-OS Software products forward SNAP/LLC frames without any additional FHS feature inspection.

Affected Products
Cisco products if they are running a vulnerable release of Cisco NX-OS Software:
Nexus 3000 Series Switches
Nexus 5500 Platform Switches
Nexus 5600 Platform Switches
Nexus 6000 Series Switches
Nexus 7000 Series Switches
Nexus 9000 Series Switches

QID Detection Logic(Authenticated):
It checks for vulnerable version of Cisco NX-OS using show version Command.

Exploitation of these vulnerabilities could allow an adjacent attacker to bypass configured first-hop security (FHS) features on the affected Cisco products.

  • CVSS V3 rated as Medium - 4.7 severity.
  • CVSS V2 rated as Medium - 5 severity.
    • Solution

    Customers are advised to refer to cisco-sa-VU855201-J3z8CKTX

    Vendor References

    CVEs related to QID 317249

    CVE-2021-27853 |
    Software Advisories
    Advisory ID Software Component Link
    cisco-sa-VU855201-J3z8CKTX URL Logo www.cisco.com/c/en/us/support/docs/csa/cisco-sa-VU855201-J3z8CKTX.html#vp
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