CVE-2021-1451 Explained : Impact and Mitigation

This article provides insight into CVE-2021-1451, a vulnerability in Cisco IOS XE Software's Easy Virtual Switching System (VSS), allowing remote code execution.

Understanding CVE-2021-1451

CVE-2021-1451 involves a critical vulnerability in the Easy VSS feature of Cisco IOS XE Software for Cisco Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches.

What is CVE-2021-1451?

The vulnerability arises due to incorrect boundary checks in Easy VSS protocol packets, enabling an unauthenticated attacker to execute arbitrary code on the device's underlying Linux OS.

The Impact of CVE-2021-1451

The security flaw could be exploited by a remote attacker to trigger a denial of service (DoS) or execute malicious code with root privileges on the affected device's operating system.

Technical Details of CVE-2021-1451

CVE-2021-1451 has a CVSSv3.1 base score of 8.1, indicating a high severity level with a network attack vector and significant impact on availability, confidentiality, and integrity.

Vulnerability Description

The vulnerability results from a buffer overflow condition when processing crafted Easy VSS protocol packets sent to UDP port 5500 on a vulnerable device.

Affected Systems and Versions

The vulnerability affects Cisco IOS XE Software on Catalyst 4500 Series and Catalyst 4500-X Series Switches.

Exploitation Mechanism

An attacker can exploit this flaw by sending specially crafted Easy VSS protocol packets while the target device is in a specific state, leading to potential code execution.

Mitigation and Prevention

To mitigate the risk associated with CVE-2021-1451, immediate actions and long-term security best practices are recommended.

Immediate Steps to Take

Users are advised to apply security updates provided by Cisco to address the vulnerability promptly.

Long-Term Security Practices

Maintaining up-to-date software, monitoring for security advisories, and implementing network segmentation can enhance overall security posture.

Patching and Updates

Regularly check for patches and updates from Cisco to protect against potential exploits of CVE-2021-1451.