CVE-2024-34009

What it actually does

Insufficient server-side validation of whether ReCAPTCHA protection is enabled allows an unauthenticated remote attacker to submit login requests that completely bypass the ReCAPTCHA check, resulting in the ability to perform authentication attempts without the intended bot-mitigation control.

Why it matters to the business

Attackers can more easily automate login attempts against user accounts, raising the risk of credential stuffing or brute-force success and potentially leading to account takeovers or increased operational load on authentication systems.

How an attack unfolds

An attacker discovers the login endpoint, crafts HTTP POST requests that omit the expected ReCAPTCHA response parameters or tokens, and submits repeated authentication attempts; because the server fails to enforce the ReCAPTCHA requirement, the requests proceed directly to credential validation, allowing the attacker to test stolen or guessed credentials at scale without triggering bot-detection mechanisms.

How to fix it

Apply the vendor-supplied patch that enforces ReCAPTCHA checks on the login page; for the affected codebase this is achieved by updating to the commit 143c2cd5bef1268751d58bbfc6c66c1d93cb9797 or later equivalent release.

How to confirm the fix worked

After patching, confirm that login requests without valid ReCAPTCHA tokens are rejected with the appropriate error response; review application configuration to ensure ReCAPTCHA remains enabled on the login page and test both successful and failed captcha scenarios.

Typical attack path

1. Map the application's login form and associated API endpoints
2. Omit or nullify ReCAPTCHA fields in crafted authentication requests
3. Submit high-volume login attempts using lists of usernames and passwords
4. Observe successful authentication responses that would normally have been blocked by ReCAPTCHA

How to detect it

Review web server and application logs for authentication POST requests that lack expected ReCAPTCHA token parameters or that receive successful responses despite missing captcha validation; correlate with high-frequency login attempts from single sources.

What your security team should do

• Immediately schedule the patch deployment for all instances of the affected software
• Monitor authentication logs for spikes in failed login attempts that bypass secondary controls
• Consider temporarily enforcing additional rate-limiting or IP-based restrictions on login endpoints until the fix is applied