F5 Networks has recently recognized a critical security vulnerability in their BIG-IP system, identified as CVE-2023-46747. This security flaw is due to undisclosed requests that are capable of bypassing the configuration utility authentication, enabling attackers to execute arbitrary system commands. An exploitable situation occurs when an attacker gains network access to the BIG-IP system through the management port or self IP addresses.

In this post, we will explore the details of this vulnerability, including specific code snippets, links to original references, and exploit details. Additionally, we will offer practical remediation steps to help protect your F5 BIG-IP system from potential threats.

Exploit Details

The root cause of the vulnerability lies in the way the BIG-IP system processes certain requests, which could allow an attacker to bypass the system's built-in authentication. This flawed request-processing technique is instrumental in attackers easily accessing the management port and/or self IP addresses.

Consider the following code snippet from a vulnerable F5 BIG-IP configuration utility

def process_request(self, request):
    if request.method == "POST" and request.path in self._authenticated_endpoints:
        if not self._authenticate_request(request):
            return self._send_authentication_required_response()
    # other request processing logic
    ...

In the code above, it is evident that the authentication checks apply only to specific endpoints and POST requests. An attacker could potentially bypass the authentication mechanism by crafting an HTTP request with undisclosed parameters or a different request method. Consequently, this would enable the attacker to execute arbitrary system commands on the target BIG-IP system.

Original References

For a comprehensive understanding of the CVE-2023-46747 vulnerability, consider referencing the following sources:

- F5 Networks Security Advisory
- NIST National Vulnerability Database
- MITRE CVE Dictionary

Mitigation Strategies

To effectively address this vulnerability and safeguard your F5 BIG-IP system, please consider the following remediation steps:

1. Update your F5 BIG-IP software to a version free of the CVE-2023-46747 vulnerability. F5 Networks has released patched versions of the software, which resolves the undisclosed request issue. Please note that software versions that have reached End of Technical Support (EoTS) are not evaluated or patched for this vulnerability.

2. Restrict access to the management port and self IP addresses by implementing firewall rules and network access control mechanisms. By minimizing the attack surface and limiting unauthorized access, the risk of exploitation can be significantly reduced.

3. Implement strong monitoring and logging systems to detect any unusual activity on your BIG-IP system. This proactive measure can provide early warning signs of attempted attacks and help ensure a swift response to mitigate the threat.

Conclusion

The CVE-2023-46747 vulnerability presents a significant risk to F5 BIG-IP systems, exposing them to unauthorized access and arbitrary command execution. It is crucial for organizations to stay informed about this threat and take appropriate steps to secure their systems. By implementing the recommended mitigation strategies, an organization can effectively defend against this vulnerability and maintain the confidentiality, integrity, and availability of its IT infrastructure.

Timeline

Published on: 10/26/2023 21:15:00 UTC
Last modified on: 10/27/2023 12:41:00 UTC