Understanding the Latest Clickjacking Vulnerability in Password Managers: A Technical Deep Dive

Inception Security
6 minutes ago
5 min read

In the ever-evolving landscape of cybersecurity threats, a new zero-day vulnerability has emerged that targets popular password managers through a sophisticated form of clickjacking. Disclosed on August 20, 2025, this DOM-based extension clickjacking exploit allows attackers to deceive users into autofilling sensitive credentials—such as usernames, passwords, two-factor authentication (2FA) codes, and even credit card details—into hidden fields on malicious websites. As a leading cybersecurity firm, Inception Security is committed to providing in-depth analysis and actionable insights to help organizations and individuals mitigate such risks. This blog post serves as a comprehensive technical reference, breaking down the mechanics of clickjacking, the specifics of this vulnerability, affected tools, vendor responses, and remediation strategies.

What is Clickjacking?

Clickjacking, also known as UI redressing, is a malicious technique where an attacker tricks a user into interacting with a hidden or disguised element on a webpage, often by overlaying transparent or opaque layers. The term originates from "click hijacking," as the user's intended click is redirected to perform an unintended action.

Core Mechanics of Clickjacking

At its foundation, clickjacking exploits the Document Object Model (DOM) and Cascading Style Sheets (CSS) to manipulate user interface (UI) elements. Here's a step-by-step technical breakdown:

Overlay Creation: An attacker crafts a malicious webpage that loads a legitimate site or extension pop-up in an iframe or via DOM injection. Using CSS properties like opacity: 0; or z-index manipulation, the attacker makes the legitimate element invisible or partially hidden while overlaying it with a deceptive UI (e.g., a fake "Play Video" button).
User Deception: The user sees and interacts with the overlay, believing they are clicking on something benign. However, the click event propagates to the hidden element beneath, triggering actions like form submissions or API calls.
Event Propagation: In the browser's event model, clicks are captured and bubbled through the DOM tree. Attackers leverage this by positioning the hidden iframe or div precisely under the cursor using absolute positioning (e.g., position: absolute; top: 0; left: 0;).

Traditional clickjacking often targets iframes and can be mitigated with HTTP headers like X-Frame-Options: DENY or Content Security Policy (CSP) directives such as frame-ancestors 'none';. However, modern variants, like the one discussed here, target browser extensions and autofill prompts, bypassing some of these protections.

Example Code Snippet for Basic Clickjacking

To illustrate, consider this simplified HTML/CSS exploit (for educational purposes only—do not deploy in production):

html

<!DOCTYPE html>
<html>
<head>
    <style>
        #overlay {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            z-index: 10;
            background: url('fake-button.png') no-repeat center;
        }
        #hidden-iframe {
            position: absolute;
            top: 0;
            left: 0;
            opacity: 0; /* Makes it invisible */
            z-index: 1;
        }
    </style>
</head>
<body>
    <div id="overlay">Click Here for Free Gift!</div>
    <iframe id="hidden-iframe" src="https://legitimate-site.com/like-button"></iframe>
</body>
</html>

In this setup, clicking the "Free Gift" overlay actually "likes" something on the hidden legitimate site. Advanced attacks use JavaScript to dynamically adjust positions based on user interactions.

The Specific Vulnerability: DOM-Based Extension Clickjacking in Password Managers

This zero-day exploit, dubbed "extension clickjacking," targets the autofill functionality of password manager browser extensions. Unlike traditional clickjacking, it doesn't rely on iframes but on manipulating the extension's pop-up or autofill dialog through DOM overlays.

How the Exploit Works

Setup: A user visits a malicious site that injects hidden form fields (e.g., <input type="text" style="display: none;"> for username/password).
Triggering Autofill: The site prompts the password manager's extension to autofill credentials, often by mimicking a login form. The extension displays a confirmation pop-up.
Overlay Deception: Using CSS (e.g., pointer-events: none; on the overlay to allow clicks to pass through), the attacker hides the pop-up under a transparent layer and overlays a fake prompt (e.g., "Click to Verify CAPTCHA"). The user clicks on the fake element to confirm the autofill into the hidden fields.
Data Exfiltration: Once autofilled, JavaScript on the malicious site captures the data and exfiltrates it via XMLHttpRequest or WebSockets.

This attack is particularly insidious because it requires only a single user click and exploits the trust users place in their password managers. It's a client-side vulnerability, leveraging browser permissions granted to extensions.

Affected Password Managers and Versions

Based on the disclosure, the following managers are vulnerable as of August 20, 2025:

Bitwarden: Version 2025.7.0 – Partial vulnerability; patch in progress.
1Password: Version 8.11.4.27 – Autofill prompt can be overlaid.
LastPass: Version 4.146.3 – Fully exploitable for credentials and 2FA.
Enpass: Version 6.11.6 – Affects desktop and browser extensions.
LogMeOnce: Version 7.12.4 – No response; highly vulnerable.
iCloud Passwords: Version 3.1.25 – Impacts Safari integration.

Managers like Dashlane, NordPass, Keeper, RoboForm, and Proton Pass have already deployed fixes, implementing visibility checks or randomized UI elements to detect overlays.

Vendor Responses and Patch Status

Vendor reactions have varied, highlighting differences in security postures:

1Password and LastPass: Classified as "out-of-scope," advising users to avoid untrusted sites. This has been criticized as victim-blaming, as the exploit can occur on seemingly legitimate pages via ad injections or compromised scripts.
Bitwarden and Enpass: Actively developing patches, expected within 48-72 hours. Bitwarden recommends disabling autofill temporarily.
Apple (iCloud Passwords): Silent on details but confirmed a fix in the next Safari update.
LogMeOnce: No public response, leaving users exposed.

Remediation Recommendations

To mitigate this vulnerability, we provide tiered recommendations for end-users, system administrators, and extension developers. These are grounded in best practices and can serve as a reference checklist.

For End-Users and Organizations

Immediate Updates: Check for and apply updates to your password manager. For example, enable auto-updates in browser extension stores.
Disable Autofill Temporarily: In vulnerable managers, turn off automatic autofill via extension settings. Manually copy-paste credentials until patches are available.
Browser Hardening:
- Use extensions like NoScript or uBlock Origin to block suspicious scripts.
- Enable site isolation in Chrome/Edge (chrome://flags/#site-isolation) to sandbox tabs.
- Avoid clicking on unfamiliar prompts; verify URLs in the address bar.
Multi-Layered Security: Combine password managers with hardware 2FA keys (e.g., YubiKey) and endpoint detection tools. Regularly audit browser extensions for permissions.
Awareness Training: Educate teams on phishing variants. Simulate attacks using tools like Evilginx to demonstrate risks.

For Developers and Extension Authors

UI Integrity Checks: Implement JavaScript to verify popup visibility before processing clicks. For instance:

javascript
function isElementVisible(el) {    
	const rect = el.getBoundingClientRect();     
	return rect.top >= 0 && rect.left >= 0 &&             		
		   rect.bottom <= (window.innerHeight || 				     									  
				document.documentElement.clientHeight) && 
            rect.right <= (window.innerWidth ||
				document.documentElement.clientWidth) &&            			window.getComputedStyle(el).opacity > 0.5; 
					// Check for transparency }

// Usage: if (!isElementVisible(popupElement)) { abortAutofill(); }

Randomized Elements: Add dynamic CSS classes or positions to popups, making static overlays harder to craft.
CSP Enforcement: In extension manifests, enforce strict CSP to prevent inline scripts: "content_security_policy": "script-src 'self'; object-src 'self';".
Event Validation: Use event.isTrusted in click handlers to ensure events originate from genuine user actions, not synthetic ones.
Reporting and Logging: Integrate telemetry to log suspicious autofill attempts, aiding in post-incident forensics.

For broader web app protection against general clickjacking, always set X-Frame-Options: SAMEORIGIN in server responses.

Conclusion

This clickjacking vulnerability underscores the delicate balance between usability and security in browser extensions. While password managers enhance productivity, they also expand the attack surface. At Inception Security, we urge proactive remediation to safeguard sensitive data. Stay vigilant, update regularly, and consider partnering with experts for vulnerability assessments. For tailored consultations or threat intelligence, contact us at info@inceptionsecurity.com (mailto:info@inceptionsecurity.com).

References: