CVE-2022-38373: FortiDeceptor Management Interface XSS Vulnerability & Exploit Details

A recent vulnerability, dubbed CVE-2022-38373, has been discovered in the FortiDeceptor management interface, affecting specific versions (4.2., 4.1. through 4.1.1, and 4..2). This vulnerability relates to an improper neutralization of input during web page generation [CWE-79] and could potentially allow an authenticated user to carry out a cross-site scripting (XSS) attack by sending requests with a specially crafted lure resource ID. This long-read post will delve into the details of this vulnerability, including code snippets, links to original references, and exploit information.

Vulnerability Details

The vulnerability lies in the FortiDeceptor management interface (versions 4.2., 4.1. through 4.1.1, and 4..2), which lacks proper input sanitization during web page generation. This lack of input filtering means that an attacker can inject malicious code into the web page, leading to a cross-site scripting (XSS) attack.

An authenticated user could exploit the vulnerability by sending specially crafted requests with a malicious lure resource ID, thereby executing the XSS attack. As a result, this could compromise the management interface and expose sensitive information or lead to unauthorized actions.

A basic example of this vulnerability being exploited might look like this

// Malicious lure_resource_id value:
var malicious_lure_resource_id = '<script>alert("XSS Attack!")</script>';

// Inject the malicious code into the web page:
document.write("Lure Resource ID: " + malicious_lure_resource_id);

In this code snippet, the attacker has created a malicious lure_resource_id variable containing a script tag that triggers an alert reading "XSS Attack!" When the document.write function adds this malicious code to the web page, it will execute, thereby demonstrating the XSS attack.

For more information on the vulnerability, check out these sources

1. Fortinet's official security advisory: https://www.fortiguard.com/psirt/FG-IR-20-339
2. MITRE's CVE entry: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-38373
3. National Vulnerability Database (NVD) entry: https://nvd.nist.gov/vuln/detail/CVE-2022-38373
4. CWE-79: https://cwe.mitre.org/data/definitions/79.html

Exploit Details

In order to exploit this vulnerability, an attacker must first be an authenticated user with access to the FortiDeceptor management interface. Once the attacker has gained access, they can then craft a specially designed HTTP request with the malicious lure resource ID and send it to the server.

Upon the server’s processing of the HTTP request containing the malicious lure resource ID, the server fails to sanitize the input, thus allowing the attacker to execute an XSS attack. The severity of this XSS attack can vary, as it may lead to unauthorized administrative actions, data manipulation, or private information leakage.

Mitigation

Fortinet has already released security patches to address this vulnerability in the affected versions of the FortiDeceptor management interface. Users are highly encouraged to apply the patches or upgrade to the latest version of the software to protect their systems from this XSS vulnerability.

Conclusion

As with any vulnerability, awareness and proper mitigation are crucial in ensuring the security of one's systems. With the information provided above on CVE-2022-38373, users of the affected FortiDeceptor management interface versions can now take appropriate steps to safeguard their systems and prevent potential exploitation.

Timeline

Published on: 11/02/2022 12:15:00 UTC
Last modified on: 11/03/2022 13:51:00 UTC