Recently, a significant security vulnerability has been identified in several Fortinet products, including FortiManager, FortiAnalyzer, FortiOS, and FortiSandbox. This vulnerability, dubbed as CVE-2022-22305, affects the way these products handle certificate validation and could potentially facilitate man-in-the-middle (MITM) attacks by unauthenticated, network adjacent attackers. To help you better understand the repercussions and exploit details of this vulnerability, we have provided an in-depth explanation, code snippets, and links to relevant references.

Vulnerability Details

CVE-2022-22305 refers to an improper certificate validation vulnerability [CWE-295] present in FortiManager 7..1 and below, FortiAnalyzer 7..2 and below, FortiOS 6.2.x and 6..x, and FortiSandbox 4..x, 3.2.x, and 3.1.x. Due to insufficient certificate validation, attackers could intercept the communication between the vulnerable products and some external peers, leading to MITM attacks.

A typical example of improper certificate validation in affected products may look like this

// Vulnerable Certificate Validation Example
bool validate_certificate(x509 *cert)
{
    // Skipping full certificate validation
    return true;
}

void establish_secure_connection() 
{
    // ...

    // Validate the server's certificate
    x509 *server_cert = get_server_certificate();
    if (validate_certificate(server_cert)) 
    {
        // Proceed with a secure connection
    }
    else 
    {
        // Certificate validation failed -- potential MITM attack
    }

    // ...
}

The validate_certificate function in the example returns true no matter what, which means the certificate validation step is essentially skipped, allowing attackers to tamper with the data in transit.

An attacker who wants to exploit this vulnerability would typically follow these steps

1. Gain access to the same network segment as the targeted system, which might be accomplished via physical access or exploiting another vulnerability on a different system within the network.

Use network sniffing tools to monitor traffic between the targeted system and external peers.

3. Identify the vulnerable communication channels and intercept transmissions by deploying a malicious server or proxy posing as a legitimate peer.

4. Modify, inject, or manipulate data in transit, potentially compromising the target system or the entire communication process.

Original References

For more information on this vulnerability and associated risks, please refer to the following sources:

1. FortiGuard Labs Security Advisory: https://www.fortiguard.com/psirt/FG-IR-21-281

2. Common Vulnerabilities and Exposures (CVE): https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-22305

3. Common Weakness Enumeration (CWE): https://cwe.mitre.org/data/definitions/295.html

Conclusion

CVE-2022-22305 is a critical security vulnerability that primarily affects certificate validation in several Fortinet products. It is crucial for organizations and individuals using these products to ensure they are using the patched versions to minimize the risks associated with this vulnerability. By being more aware of security vulnerabilities like this one, we can all contribute to a more secure digital environment.

Timeline

Published on: 09/01/2023 12:15:08 UTC
Last modified on: 11/07/2023 03:43:51 UTC