CVE-2020-5921 Explained : Impact and Mitigation

This CVE involves a vulnerability in BIG-IP versions 11.6.1-11.6.5.2, 12.1.0-12.1.5.1, 13.1.0-13.1.3.4, 14.1.0-14.1.2.6, 15.0.0-15.0.1.3, and 15.1.0-15.1.0.4 that can lead to a Denial of Service (DoS) condition due to a Syn flood attack affecting VIPRION hosts with multiple blades.

Understanding CVE-2020-5921

This CVE identifies a specific vulnerability in F5's BIG-IP software that can be exploited to cause a DoS condition on vulnerable systems.

What is CVE-2020-5921?

This CVE refers to a flaw in BIG-IP versions that allows a Syn flood attack to generate a large number of MCPD context messages, leading to memory consumption and eventual MCPD failure.

The Impact of CVE-2020-5921

The vulnerability affects VIPRION hosts with two or more blades installed, potentially causing a DoS condition by overwhelming the system with MCPD context messages.

Technical Details of CVE-2020-5921

This section delves into the technical aspects of the vulnerability.

Vulnerability Description

The vulnerability allows attackers to exploit a Syn flood attack to flood MCPD context messages, consuming memory and causing MCPD failure.

Affected Systems and Versions

BIG-IP versions 11.6.1-11.6.5.2
BIG-IP versions 12.1.0-12.1.5.1
BIG-IP versions 13.1.0-13.1.3.4
BIG-IP versions 14.1.0-14.1.2.6
BIG-IP versions 15.0.0-15.0.1.3
BIG-IP versions 15.1.0-15.1.0.4

Exploitation Mechanism

Attackers can exploit this vulnerability by launching a Syn flood attack to overwhelm the system with MCPD context messages, leading to memory exhaustion and MCPD failure.

Mitigation and Prevention

Protecting systems from this vulnerability requires immediate actions and long-term security practices.

Immediate Steps to Take

Apply vendor-supplied patches or updates to mitigate the vulnerability.
Implement network-level protections to detect and block Syn flood attacks.

Long-Term Security Practices

Regularly update and patch software to address known vulnerabilities.
Monitor network traffic for unusual patterns that may indicate a DoS attack.

Patching and Updates

F5 has released patches to address this vulnerability. Ensure timely application of these patches to secure affected systems.