CVE-2021-23004 : Exploit Details and Defense Strategies

A vulnerability has been identified in BIG-IP software versions 11.6.x to 16.0.x that could allow for the creation of Multipath TCP (MPTCP) forwarding flows on virtual servers without MPTCP enabled, potentially leading to Denial of Service (DoS) attacks.

Understanding CVE-2021-23004

This CVE impacts various versions of BIG-IP software, allowing the establishment of MPTCP flows without the necessary configuration, posing a risk of DoS attacks.

What is CVE-2021-23004?

CVE-2021-23004 is a vulnerability found in BIG-IP software versions 16.0.x, 15.1.x, 14.1.x, 13.1.x, 12.1.x, and 11.6.x, enabling the creation of MPTCP flows on virtual servers without proper MPTCP configuration.

The Impact of CVE-2021-23004

The vulnerability could be exploited by malicious actors to trigger DoS attacks by establishing MPTCP forwarding flows on standard virtual servers, even when MPTCP is not enabled.

Technical Details of CVE-2021-23004

This section provides specific technical details regarding the vulnerability.

Vulnerability Description

In BIG-IP versions 11.6.x to 16.0.x, the issue allows for the generation of MPTCP forwarding flows on virtual servers that lack MPTCP configuration, potentially resulting in DoS attacks.

Affected Systems and Versions

The vulnerability impacts BIG-IP software versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2, 14.1.x before 14.1.3.1, 13.1.x before 13.1.3.6, 12.1.x before 12.1.5.3, and 11.6.x before 11.6.5.3.

Exploitation Mechanism

By exploiting this vulnerability, threat actors can create MPTCP flows on virtual servers without the proper MPTCP configuration, opening avenues for DoS attacks.

Mitigation and Prevention

To address CVE-2021-23004, immediate steps should be taken along with long-term security practices.

Immediate Steps to Take

Administrators are advised to update to the patched versions to mitigate the vulnerability. Additionally, enabling MPTCP only on servers where it is required can reduce the attack surface.

Long-Term Security Practices

Implementing network segmentation and regular security training for staff can enhance overall security posture and resilience against potential attacks.

Patching and Updates

Regularly check for security updates from F5 for BIG-IP software and apply them promptly to prevent exploitation of known vulnerabilities.