CVE-2025-22467 - Stack-Based Buffer Overflow in Ivanti Connect Secure (RCE Exploit Walkthrough)

CVE-2025-22467 impacts Ivanti Connect Secure, a popular VPN solution used by organizations around the world. This newly disclosed vulnerability is a stack-based buffer overflow that exists in all versions *before 22.7R2.6*. It allows a remote authenticated attacker to execute arbitrary code on the server — otherwise known as Remote Code Execution (RCE). Since Ivanti Connect Secure is often internet-facing and provides protected access to internal networks, this vulnerability is highly critical.

This post gives you an accessible, technical breakdown of CVE-2025-22467, including technical context, sample code illustrating the bug, exploiting the stack overflow, and essential info to defend your networks.

Official reference:

Ivanti Security Advisory — CVE-2025-22467

What Is a Stack-Based Buffer Overflow?

A stack-based buffer overflow occurs when a program copies more data into a buffer than it was intended to hold, and the buffer is located on the stack (the call stack). This can overwrite critical data like return addresses, allowing attackers to control program execution — often leading to RCE.

> Think of it like stuffing too many clothes into a suitcase, causing it to burst open and spill out, possibly hiding things or causing a mess that lets someone else sneak their belongings in.

Where Is the Bug?

The overflow occurs in a web interface endpoint handling user-supplied parameters after authentication. An insufficiently checked parameter is copied into a fixed-size stack variable using unsafe string functions (like strcpy or sprintf), without proper bounds checking.

Below is illustrative (simplified) code, likely similar to the root of the problem

void handle_request(char *user_input) {
    char buffer[256];

    // Vulnerable: Does not check length of user_input!
    strcpy(buffer, user_input);  // If user_input > 255 bytes => buffer overflows

    // ... Do something with buffer ...
}

Note: The real vulnerable function is more complex, but the core issue is unchecked copying of user input.

2. Send a specially-crafted request (usually a large parameter in a POST or GET field) to the vulnerable endpoint.

The attacker’s payload overwrites the return address or function pointers on the stack.

5. When the function returns... attacker code executes (RCE!). Malware can be uploaded, backdoors can be placed, VPN configuration can be altered.

Suppose the vulnerable parameter is named hostname

POST /vpn/ssl/webhost HTTP/1.1
Host: victim.example.com
Cookie: AUTH_TOKEN=[valid_token]
Content-Type: application/x-www-form-urlencoded

hostname=AAAAAAAAA...AAAA<shellcode bytes here since buffer is on stack>

The actual exploit would use a payload that carefully fits N bytes to overflow the buffer, followed by a fake return address and shellcode that gives the attacker a system shell or downloads a remote payload.

Real-World Impact

- System compromise: The attacker gets unfettered command-line access as the service account (often root or SYSTEM).

Persistence: Attackers may install rootkits or backdoors.

Notably, since authentication is required, mass Internet scanning is harder but not impossible for attackers who can phish credentials or target insiders.

References and Further Reading

- Ivanti Official Advisory for CVE-2025-22467
- MITRE CVE Record for CVE-2025-22467
- How Stack-Based Buffer Overflows Work (OWASP)
- Previous Ivanti (Pulse Secure) VPN RCE Advisories

Restrict VPN portal access: Use IP allowlists or multifactor authentication.

3. Monitor for signs of attack: Unusual logins, large parameter POSTs, service restarts, suspicious new accounts.

Rotate credentials for all VPN users post-upgrade.

5. Review and segment your network so that a compromised VPN server can't reach crown-jewel internal systems directly.

Conclusion

CVE-2025-22467 is a textbook example of why buffer overflows remain a severe threat in network appliances. Even major vendors can slip up with unsafe coding practices, and attackers are quick to exploit any chink in the armor. If your organization uses Ivanti Connect Secure, patch now — and stay vigilant!

*Got questions or insights about CVE-2025-22467? Share them below!*

Timeline

Published on: 02/11/2025 16:15:50 UTC
Last modified on: 02/20/2025 15:53:06 UTC