The vulnerability CVE-2024-26006 is an Improper Neutralization of Input During Web Page Generation (CWE-79), which affects the FortiOS version 7.4.3 and below, version 7.2.7 and below, version 7..13 and below, and FortiProxy version 7.4.3 and below, version 7.2.9 and below, and version 7..16 and below Web SSL VPN UI. This vulnerability enables a remote unauthenticated attacker to execute a Cross-Site Scripting (XSS) attack through a malicious Samba server.
Exploit Details
Cross-Site Scripting (XSS) occurs when an application includes untrusted data in a new web page without proper validation and escaping. This enables an attacker to execute malicious scripts in the user's browser, which can lead to unauthorized access or the compromise of user data.
In the case of CVE-2024-26006, an attacker can exploit the vulnerability by setting up a malicious Samba server that injects malicious HTML or JavaScript code. When a user connects to the vulnerable FortiOS or FortiProxy Web SSL VPN UI, the injected code is executed in the user's browser.
Here's a simplified example of the malicious Samba server setup
import smbserver
# Set up malicious payload
payload = "<script>alert('XSS');</script>"
# Configure the Samba server
server = smbserver.SimpleSMBServer()
server.addShare("malicious_share", "/path/to/share")
server.setSMB2Support(True)
server.setSMBChallenge(payload.encode("utf-8"))
# Start the Samba server
print("Starting malicious Samba server...")
server.start()
When a user attempts to access the malicious share through the vulnerable FortiOS or FortiProxy Web SSL VPN UI, the XSS payload (<script>alert('XSS');</script>) would be executed in their browser, alerting the user with a popup displaying the text 'XSS'.
Original References
1. Fortinet Security Advisory: FG-IR-21-055
2. Common Weakness Enumeration: CWE-79
3. National Vulnerability Database: CVE-2024-26006
Mitigations
Users should upgrade their FortiOS and FortiProxy systems to the latest versions mentioned below, which contain the required security patches:
Conclusion
The improper neutralization of input during web page generation (CWE-79) found in certain versions of FortiOS and FortiProxy makes them vulnerable to remote unauthenticated attackers who may initiate a Cross-Site Scripting attack through a malicious Samba server. It is of utmost importance for users to upgrade their systems to the latest versions containing security patches to prevent unauthorized access or compromise of user data.
Timeline
Published on: 03/14/2025 10:15:14 UTC