CVE-2023-33306 Explained : Impact and Mitigation

This article provides an in-depth look at CVE-2023-33306, a vulnerability in Fortinet FortiOS and FortiProxy that could lead to a denial of SSLVPN service.

Understanding CVE-2023-33306

CVE-2023-33306 is a null pointer dereference vulnerability found in Fortinet FortiOS versions before 7.2.5, before 7.0.11, and before 6.4.13, as well as FortiProxy versions before 7.2.4 and before 7.0.10. This flaw can be exploited by an attacker through a specifically crafted request in the bookmark parameter to launch a denial of SSLVPN service attack.

What is CVE-2023-33306?

This CVE refers to a null pointer dereference vulnerability in Fortinet FortiOS and FortiProxy, allowing attackers to disrupt SSLVPN service by exploiting certain versions of the software.

The Impact of CVE-2023-33306

The vulnerability can have a significant impact on the availability of SSLVPN service, potentially leading to service denial for legitimate users. Attackers can exploit this flaw to disrupt critical communication channels and cause service interruptions.

Technical Details of CVE-2023-33306

This section delves into the specific technical details related to the CVE, including a description of the vulnerability, affected systems, and the exploitation mechanism.

Vulnerability Description

A null pointer dereference in Fortinet FortiOS before 7.2.5, before 7.0.11, and before 6.4.13, FortiProxy before 7.2.4, and before 7.0.10 allows attackers to launch a denial of SSLVPN service attack via a specially crafted request in the bookmark parameter.

Affected Systems and Versions

The vulnerability impacts Fortinet FortiOS versions 7.2.0 to 7.2.4, 7.0.0 to 7.0.10, and 6.4.0 to 6.4.12, as well as FortiProxy versions 7.2.0 to 7.2.3 and 7.0.0 to 7.0.9.

Exploitation Mechanism

Attackers can exploit this vulnerability by sending a specifically crafted request in the bookmark parameter, triggering a null pointer dereference and leading to a denial of SSLVPN service.

Mitigation and Prevention

This section outlines steps that organizations and users can take to mitigate the risks associated with CVE-2023-33306.

Immediate Steps to Take

Upgrade to FortiOS version 7.4.0 or above to address the vulnerability.
Upgrade to FortiOS version 7.2.5 or above.
Upgrade to FortiOS version 7.0.11 or above.
Upgrade to FortiOS version 6.4.13 or above.
Upgrade to FortiProxy version 7.2.4 or above.
Upgrade to FortiProxy version 7.2.3 or above.
Upgrade to FortiProxy version 7.0.9 or above.
Upgrade to FortiProxy version 7.0.10 or above.

Long-Term Security Practices

Apart from immediate upgrades, organizations should implement robust security practices, including regular software updates, threat monitoring, and access control mechanisms, to enhance overall cybersecurity posture.

Patching and Updates

Regularly check for security patches and updates from Fortinet to ensure that your systems are protected against known vulnerabilities.