CVE-2021-34713 : Security Advisory and Response

A vulnerability in the Layer 2 punt code of Cisco IOS XR Software running on Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, adjacent attacker to cause the affected line card to reboot. This vulnerability is due to incorrect handling of specific Ethernet frames that cause a spin loop, making the network processors unresponsive. An attacker could exploit this weakness by sending specific types of Ethernet frames to the segment where the affected line cards are attached, resulting in a potential reboot.

Understanding CVE-2021-34713

This section delves into the details of the CVE-2021-34713 vulnerability.

What is CVE-2021-34713?

The vulnerability in Cisco IOS XR Software allows an adjacent attacker to trigger a reboot in the affected line card by sending specific Ethernet frames, impacting network processors' responsiveness.

The Impact of CVE-2021-34713

The vulnerability's high availability impact and severity level of 7.4 highlight the potential for an attacker to disrupt network operations by causing reboots in affected line cards.

Technical Details of CVE-2021-34713

This section covers the technical aspects of CVE-2021-34713.

Vulnerability Description

The vulnerability arises due to improper handling of Ethernet frames, leading to a spin loop that can render network processors unresponsive.

Affected Systems and Versions

Cisco IOS XR Software running on ASR 9000 Series Routers is susceptible to this vulnerability.

Exploitation Mechanism

An unauthenticated, adjacent attacker can exploit this vulnerability by manipulating specific types of Ethernet frames on the network segment.

Mitigation and Prevention

Explore the measures to mitigate and prevent the CVE-2021-34713 vulnerability.

Immediate Steps to Take

Immediately apply vendor-released patches or workarounds to safeguard against potential attacks exploiting this vulnerability.

Long-Term Security Practices

Implement robust network security measures, including network segmentation and access controls, to reduce the risk of unauthorized access.

Patching and Updates

Regularly monitor vendor security advisories and apply security patches or updates to address known vulnerabilities.