CVE-2023-4481 Explained : Impact and Mitigation

This CVE details an Improper Input Validation vulnerability in the Routing Protocol Daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved that allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS) attack.

Understanding CVE-2023-4481

This vulnerability affects Junos OS and Junos OS Evolved, specifically impacting the BGP (Border Gateway Protocol) modules and the rpd (Routing Protocol Daemon).

What is CVE-2023-4481?

The CVE-2023-4481 vulnerability permits an unauthenticated attacker to trigger a DoS attack by sending specific crafted BGP UPDATE messages over an established BGP session. This can lead to the termination of BGP sessions with an UPDATE message error, potentially affecting remote systems as well. The issue can result in a sustained DoS condition for impacted devices, affecting both eBGP and iBGP in IPv4 and IPv6 environments.

The Impact of CVE-2023-4481

The impact of this vulnerability is classified as CAPEC-28 Fuzzing, which involves sending random data to an application to discover vulnerabilities.

Technical Details of CVE-2023-4481

The vulnerability has a CVSSv3.1 base score of 7.5, indicating a high severity issue with low attack complexity, impacting availability. The attack vector is through the network with no privileges required.

Vulnerability Description

The vulnerability arises from improper input validation in the rpd component of Juniper Networks Junos OS and Junos OS Evolved, allowing for remote DoS attacks.

Affected Systems and Versions

The affected products include Junos OS versions less than 23.4R1 and Junos OS Evolved versions less than 23.4R1-EVO.

Exploitation Mechanism

By sending crafted BGP UPDATE messages over an established BGP session, an attacker can trigger a DoS condition on vulnerable devices.

Mitigation and Prevention

To address CVE-2023-4481, users are advised to follow certain steps to mitigate the risk and prevent potential attacks.

Immediate Steps to Take

Implement the provided workaround to configure BGP error tolerance.
Monitor for updated software releases and apply patches promptly.

Long-Term Security Practices

Regularly update software to the latest patched versions.
Implement network security best practices to reduce vulnerabilities.

Patching and Updates

Ensure that the affected Junos OS and Junos OS Evolved versions are updated to 23.4R1 or later to resolve the vulnerability. Follow the recommended configuration changes to prevent exploitation.

By following these mitigation strategies and staying informed about relevant security advisories, users can strengthen the security posture of their systems and networks against CVE-2023-4481.