Should You Accept Website Cookies? A Cybersecurity Expert‘s Guide
As a cybersecurity professional with over a decade of experience specializing in cloud data security, one of the questions I‘m most frequently asked is whether it‘s safe to accept cookies on websites. The answer is nuanced and depends on the specific circumstances. In this in-depth guide, I‘ll break down everything you need to know to make informed decisions about cookies and protect your data.
What Exactly Are Cookies?
Cookies are small text files that websites place on your device to store information about you and your interactions with the site. They were invented in 1994 by Netscape programmer Lou Montulli as a way to enable e-commerce shopping carts to remember their contents from page to page.
Some common examples of data stored by cookies include:
- Login credentials
- Site preferences and settings
- Contents of shopping carts
- Browsing history on the site
- Form field entries
Cookies allow websites to provide personalization, remember your actions from one page to the next, and avoid having to re-enter information. As of 2020, it‘s estimated that over 80% of websites use cookies in some form.
First-Party vs. Third-Party Cookies
Not all cookies function the same way. First-party cookies are directly placed by the website domain you are visiting. These are generally used for essential site functionality like authentication, storing settings, and keeping you logged in.
Third-party cookies, on the other hand, are created by domains other than the one you‘re on, such as advertisers and analytics firms. They are typically used for cross-site tracking, ad targeting, and data collection. A single site may utilize dozens of third-party cookies.
Here‘s an example of how third-party tracking works: let‘s say you‘re shopping for a new pair of shoes, and visit several different retailers‘ sites to compare prices and styles. On each site, a third-party advertising cookie is dropped.
Later, while browsing totally different sites, you start seeing ads for the exact shoes you were just looking at. Behind the scenes, the advertising cookie tracked your browsing from site to site and shared that data to enable retargeted ads that follow you around the web.
The table below shows some key differences between first and third-party cookies:
| Cookie Type | Set By | Visibility | Typical Purposes |
|---|---|---|---|
| First-party | Website domain you visit | Only the originating site | Essential functionality, personalization |
| Third-party | Other domains | Any site loading the third-party | Cross-site tracking, ads, data collection |
Session vs. Persistent Cookies
Another key distinction is between session and persistent cookies. Session cookies only remain active while you keep your browser open and automatically delete once you close out your session. These are used for things like keeping items in your shopping cart while clicking around a store‘s site.
Persistent cookies, as the name implies, remain stored on your device for a set period of time, which can range anywhere from a few days to a few years after your initial visit. These enable long-term tracking and are how sites can remember your preferences from one visit to the next.
The Convenience vs. Privacy Tradeoff
Cookies underpin much of the modern web experience – everything from single sign-on to intelligent recommendations relies on cookies to function. Accepting them across the board enables a smoother, more personalized browsing experience.
However, this convenience comes at a cost to privacy. An estimated 64% of tracking cookies belong to Google, giving the advertising giant an incredible amount of insight into your demographics and online behavior, which it uses to power its $135 billion annual ad business.
Data from cookies can reveal highly personal information, like health conditions, political affiliations, sexual orientation, and more. This is part of what enables creepily specific targeted ads. According to a 2019 Pew Research survey, 79% of Americans are concerned about how companies use their data.
Regulations and Cookie Notices
In response to privacy concerns, recent regulations like the EU‘s General Data Protection Regulation (GDPR) and the California Consumer Privacy Act (CCPA) require websites to obtain explicit user consent for data collection, including through cookies. This is why you now see cookie notification banners on nearly every site you visit.
However, simply opting out of cookies doesn‘t necessarily mean your data isn‘t being collected through other tracking methods. For example, browser fingerprinting uses attributes like your device, operating system, and installed fonts to create a unique identifier. An estimated one-third of the most popular websites use browser fingerprinting.
The Dark Side of Cookies: Cyberattacks and Data Breaches
In addition to privacy issues, cookies can also enable cyberattacks and data breaches. Since cookies often store sensitive information like authentication tokens and session IDs, they are an attractive target for hackers.
Through methods like cross-site scripting (XSS) and cross-site request forgery (CSRF), attackers can hijack legitimate cookies to impersonate users and gain unauthorized account access. This is why you should never accept cookies over unsecured public WiFi networks.
In 2018, the Marriott/Starwood data breach exposed the personal details of over 300 million people. The attackers remained undetected on Starwood‘s network for four years, in part by using stolen cookies to disguise their activity as legitimate.
Best Practices for Managing Cookie Risk
So what‘s the best approach for balancing convenience and privacy/security? As a cybersecurity professional, here are my top recommendations:
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Only accept cookies from reputable, secure sites (look for "https" in the URL). Be wary of unfamiliar third-party domains.
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Use browser settings or extensions to automatically block third-party cookies and trackers. In Chrome, go to Settings > Privacy and security > Cookies and other site data and select "Block third-party cookies." Other popular content-blocking extensions include uBlock Origin and Privacy Badger.
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Regularly clear out your cookies, especially after logging into sensitive sites or using a public computer. You can configure your browser to automatically delete cookies on exit.
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Use ad blockers to prevent tracking and potential malware delivery through advertising cookies. I recommend open source options like AdBlock Plus and AdGuard.
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For extra protection, enable first-party isolation in Firefox or use a privacy-focused browser like Brave that blocks cross-site cookies by default. Consider tools like Cookie Autodelete to automatically remove cookies not whitelisted.
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Embrace the future of cookieless advertising. Google has announced plans to phase out third-party cookies in Chrome by 2022 and is developing a "privacy sandbox" to enable ad targeting without cross-site tracking. Apple is also rolling out intelligent tracking prevention in Safari.
Cookies: A Necessary Evil?
In summary, cookies are deeply embedded into the fabric of today‘s web, for better and for worse. While they enable helpful personalization and functionality, they can also jeopardize user privacy and security when misused for invasive tracking and cyberattacks.
My advice is to be highly selective about which cookies you accept. Opt for the convenience of first-party cookies on trusted sites, but block third-party trackers and be vigilant about clearing out cookies regularly.
Ultimately, we need better privacy standards that give users transparency and control over their data. Proposals like the Global Privacy Control aim to streamline consent and empower users to universally opt out of data sharing.
The cookiepocalypse may be coming, but that doesn‘t mean we have to accept the status quo in the meantime. By adopting privacy-conscious browsing habits, we can have our cookies and eat them too. Stay safe out there!