Malicious Cookie Buttons

TL;DR

Yes, a website’s ‘Accept cookies’ button can be malicious. Attackers can compromise these buttons to deliver malware, redirect you to phishing sites, or steal your data. Always keep your software updated and use reputable security tools.

How Cookie Buttons Can Be Compromised

1. Compromised JavaScript: The most common method is injecting malicious code into the JavaScript that handles the cookie button’s functionality. This can happen if a website’s code is vulnerable (e.g., due to unpatched security flaws) or through supply chain attacks affecting third-party libraries used on the site.
2. Cross-Site Scripting (XSS): If a website doesn’t properly sanitise user input, an attacker could inject malicious JavaScript that runs when someone clicks the cookie button.
3. Man-in-the-Middle Attacks: On unsecured networks (like public Wi-Fi), attackers can intercept your connection and modify the website’s code in real-time, replacing the legitimate cookie button script with a harmful one.
4. Phishing Overlays: A malicious script could display a fake cookie consent banner over the real one, tricking you into clicking something that downloads malware or steals your credentials.

What Can Happen If You Click a Malicious Cookie Button?

• Malware Download: The button could trigger a download of viruses, trojans, or other malicious software onto your computer.
• Redirection to Phishing Sites: You might be sent to a fake website that looks like a legitimate login page (e.g., for your bank), designed to steal your username and password.
• Data Theft: The script could attempt to steal cookies, session tokens, or other sensitive information stored in your browser.
• Cryptojacking: Your computer’s resources could be used to mine cryptocurrency without your knowledge.

How to Protect Yourself

1. Keep Your Software Updated: Regularly update your operating system, web browser, and all plugins (e.g., Flash, Java). Updates often include security patches that fix vulnerabilities attackers can exploit.

   # Example - updating packages on Debian/Ubuntu

   sudo apt update && sudo apt upgrade

2. Use a Reputable Antivirus Program: A good antivirus program can detect and block malware before it infects your computer.
3. Browser Extensions for Security: Consider using browser extensions like uBlock Origin (for blocking malicious scripts) or Privacy Badger (to limit tracking).
4. Be Wary of Suspicious Websites: Avoid visiting websites that look untrustworthy or have a poor reputation. Check the website’s URL and security certificate before entering any personal information.
   • Look for ‘https://’ in the address bar (the ‘s’ indicates a secure connection).
   • Click the padlock icon to view the website’s security certificate.
5. Use a Firewall: A firewall can help block unauthorized access to your computer.
6. Clear Your Browser Cookies Regularly: This reduces the amount of data that could be stolen if a cookie is compromised. Most browsers have options for clearing cookies in their settings.

Checking for Suspicious Activity

1. Scan with Antivirus/Anti-Malware: Run a full system scan to check for any malicious software that may have been installed.
2. Review Browser Extensions: Check your browser extensions and remove any you don’t recognise or trust.
   • Chrome: chrome://extensions
   • Firefox: about:addons
3. Monitor Network Activity: Use a network monitoring tool to see if your computer is sending or receiving data from suspicious sources.