Quick definition: Supercookies are persistent tracking identifiers injected at the network level by service providers or stored in hidden browser caches. Unlike regular cookies, they cannot be easily deleted through standard browser settings.
Explanation
A supercookie is a persistent tracking technology designed to identify and monitor users across the internet. Unlike traditional HTTP cookies, which are stored within a browser’s designated folder and easily cleared by users, supercookies operate by exploiting alternative storage locations or network-level data injection. They often manifest as Unique Identifier Headers (UIDH) inserted into web traffic by Internet Service Providers or as “zombie cookies” hidden in the browser cache, Flash storage, or HSTS flags. These methods allow trackers to recreate deleted cookies and follow user behavior across different browsers and private sessions.
A common misconception is that supercookies are simply a more powerful version of standard cookies. In reality, they are not technically cookies at all; they are a collection of diverse tracking techniques that bypass standard privacy controls. Another myth is that clearing browser history or using “Incognito” mode provides protection. Because they reside outside the browser’s standard storage or are injected at the network level, they remain active unless blocked by advanced tools like VPNs or specific browser partitioning.
Why it matters
- – Helps prevent advertisers and service providers from building a detailed, long-term profile of your browsing habits and personal interests
- – Ensures that your choice to clear your browser history and cookies is respected by stopping trackers from secretly recreating deleted data
- – Reduces the risk of third parties identifying your device across different websites and networks without your explicit consent or knowledge
How to check or fix
- – Clear your entire browser cache, history, and site data regularly to remove persistent identifiers hidden in storage or image files
- – Prioritize browsing on encrypted websites using HTTPS to prevent network-level tracking headers from being injected into your traffic
- – Use a virtual private network to hide your network details and prevent your service provider from inserting unique identification headers
- – Enable advanced privacy settings in your browser that partition network states and caches to stop trackers from following you across different sites
- – Utilize private or incognito browsing modes to ensure that session data and temporary files are deleted immediately after you close the window
- – Adjust your browser settings to block third-party cookies and limit the ability of external scripts to store data in obscure locations
Related terms
Cookies, Tracking Cookies, Browser Fingerprinting, Evercookies, HTML5 Local Storage, Privacy Settings
FAQ
Q: What is a supercookie?
A: A supercookie is a persistent tracking identifier stored outside traditional browser cookie storage, such as in the browser cache, HTML5 storage, or injected into network headers by an ISP. Unlike standard cookies, they are difficult to detect and can survive browser resets or cookie deletion.
Q: How do supercookies differ from regular cookies?
A: Regular cookies are managed by the browser and easily cleared by users, while supercookies exploit alternative storage methods or network-level injections to remain persistent. They can even “respawn” deleted regular cookies by pulling data from hidden storage locations.
Q: How can I protect myself from supercookies?
A: You can mitigate supercookies by using privacy-focused browsers that partition network state, employing a reliable VPN to hide traffic from your ISP, and using browser extensions that block trackers and scripts. Regularly clearing your browser cache and disabling outdated plugins like Flash also helps reduce exposure.