CVE-2023-5359 - How W3 Total Cache’s Google OAuth API Secrets Leaked Sensitive Info (with Exploit Details)

If you use WordPress, chances are you’ve heard of the W3 Total Cache plugin. It helps speed up your website and is super popular — but up until version 2.7.5, it had a major *oops moment*. In this post, I’ll break down the vulnerability (CVE-2023-5359), show you what exactly went wrong in the code with plain English explanations, how attackers could take advantage of it, and what you should do now.

Exclusive: I’m going deeper than the usual summaries! Stick around and you’ll even see a code snippet and exploit flow.

What is CVE-2023-5359?

CVE-2023-5359 is a vulnerability where the W3 Total Cache plugin for WordPress accidentally left sensitive Google OAuth API secrets in their public plugin source code. Anyone—without logging in—could see these secrets.

This is a big deal, because OAuth secrets are like keys: with them, hackers could impersonate W3 Total Cache to Google and potentially access user account info.

Versions: Up to and including 2.7.5

- Main risk: Unauthenticated attackers can fetch OAuth secrets and use them to pretend to be the plugin

Trick Google into thinking they’re the “real” W3 Total Cache plugin

- Access info about users who authorized W3 Total Cache (like their public profile, perhaps email, settings, etc.), depending on permissions granted

It does NOT let hackers hack your website or WordPress admin. But, it could let them interact with Google APIs as the plugin.

Code Snippet: The Oops Exposed Secret

Here’s a simplified look at the kind of code that caused the problem. These constants (real ones are now redacted) were found right inside a main PHP file visible to anyone who downloads the plugin:

// File: w3-total-cache/inc/Google/Auth/OAuth2.php (example location)
define('W3TC_GOOGLE_CLIENT_ID',    '12345-apps.googleusercontent.com');
define('W3TC_GOOGLE_CLIENT_SECRET','SuperSecretStringHere');

This is bad, because simply browsing the plugin files (which are public or downloadable from WordPress.org) shows the OAuth secrets. You don’t need to be logged in or have special permissions!

Links to References

- Official Plugin Page
- Patch (Changelog)
- Vulnerability Advisory - Patchstack
- Wordfence Advisory

1. Find the Secrets

Anyone can download the plugin ZIP or view the repo.

Inside, they read the code or “grep” for 'client_secret' or similar, and discover

define('W3TC_GOOGLE_CLIENT_ID',    '12345-apps.googleusercontent.com');
define('W3TC_GOOGLE_CLIENT_SECRET','SuperSecretStringHere');

2. Authorize as W3 Total Cache

The attacker uses these creds to create OAuth requests, *as if they are* the legit plugin.

import requests

payload = {
    "client_id": "12345-apps.googleusercontent.com",
    "client_secret": "SuperSecretStringHere",
    "grant_type": "client_credentials"
}
r = requests.post('https://oauth2.googleapis.com/token';, data=payload)
print(r.json())

### 3. Gain Token, Fetch User Info (If user previously authorized the plugin with their Google account)

They might get information (like email or profile info) that W3 Total Cache was allowed to see.

Note: This only works for users who *already* authorized W3 Total Cache to access their Google account.

How Does This Happen?

Developers often place secrets in code for internal testing, but if you publish those files online (like in WordPress plugins), the whole world sees them.
Tip: API secrets should be stored on a private server (like via environment variables), *never in public code*.

Fix & Patch

The good news:

Update to version 2.8. or higher, which removes the sensitive info from public code.

## Quick Summary/Checklist

Are you a WordPress site owner? Update W3 Total Cache to the latest version.

- Worried about your site being hacked? — This vulnerability does *not* let hackers attack your WordPress directly.
- Did you ever link your Google account inside W3 Total Cache? If so, revoke access and re-authorize after the update.

Final Thoughts

CVE-2023-5359 is a classic example showing why API keys and secrets don’t belong in public code, ever. As a WordPress user, just update your plugins. As a developer, remember: secrets stay secret.


References:
- WordPress Plugin Page
- Patchstack Database

Timeline

Published on: 09/25/2024 01:15:39 UTC
Last modified on: 09/30/2024 14:19:15 UTC