CVE-2021-1625 : What You Need to Know

A vulnerability in the Zone-Based Policy Firewall feature of Cisco IOS XE Software has been identified, potentially allowing an unauthenticated remote attacker to manipulate traffic classification.

Understanding CVE-2021-1625

This CVE, published on September 22, 2021, exposes a security flaw in the Cisco IOS XE Software Zone-Based Policy Firewall, impacting network traffic classification.

What is CVE-2021-1625?

The vulnerability in Cisco IOS XE Software pertains to the Zone-Based Policy Firewall feature, enabling attackers to affect traffic classification by exploiting flaws in UDP and ICMP flows handling.

The Impact of CVE-2021-1625

If successfully exploited, this vulnerability could permit attackers to inject traffic through the Zone-Based Policy Firewall, leading to misclassification and inaccurate reporting.

Technical Details of CVE-2021-1625

This section outlines the specifics of the vulnerability.

Vulnerability Description

The vulnerability allows unauthenticated remote attackers to interfere with the traffic classification process of the Zone-Based Policy Firewall due to unchecked ICMP and UDP responder-to-initiator flows.

Affected Systems and Versions

The affected product is Cisco IOS XE Software, with all versions susceptible to this vulnerability.

Exploitation Mechanism

Attackers can exploit this vulnerability by attempting to pass UDP or ICMP flows through the network, bypassing the firewall's classification mechanism.

Mitigation and Prevention

To secure your systems from this vulnerability, certain steps need to be taken.

Immediate Steps to Take

Ensure to apply relevant patches from Cisco's security advisory to mitigate the risk posed by this vulnerability.

Long-Term Security Practices

Regularly update and monitor your systems to protect against potential vulnerabilities and exploits.

Patching and Updates

Stay informed about security updates and patches provided by Cisco to safeguard your network infrastructure.