Security researchers have said that your web browser history, including sites viewed using an incognito window, can easily be recovered and accessed online.
Speaking at the DefCon hacking conference in Las Vegas, security experts Svea Eckert and Andreas Dewes explained how they were able to gather information on the online habits of more three million Germans without their knowledge.
Eckert and Dewes also claim that they were able to obtain the web browser history of scores of prominent figures such as politicians and judges.
The pair detailed how they used so called ‘clickstreams’ to reveal the private viewing habits of internet users.
Clickstreams are a digital record of every click people make when visiting a website and are used by companies to help deliver targeted advertising to users.
The clickstream data is meant to be anonymous and indecipherable to other users.
However, Eckert and Dewes said that security measures in place to protect the data was “trivial” and could be easily circumvented, allowing them to access a treasure trove of private web browsing data.
Eckert and Dewes said they could then identify users by cross checking the data with posts users had made on social media, like a tweet or video shared from YouTube.
As part of their research, the pair were able to identify a judge and politician whose private browsing data revealed pornography and drug habits, which could make them prime targets for blackmail.
Speaking to the BBC, Mr Dewes said: “The public information available about users is growing so it’s getting easier to find the information to do the de-anonymisation.
“It’s very, very difficult to de-anonymise it even if you have the intention to do so.”
“This could be so creepy to abuse,” added Ms Eckert.
“You could have an address book and just look up people by their names and see everything they did.”