Twitter Reveals That Firefox Cached Private Data For Up to 7 Days

Twitter disclosed an issue in the way the Mozilla Firefox web browser cached data that may have lead to private media shared in DMs and data downloads being inadvertently stored in the browser's cache.

If you use Firefox for browsing Twitter's platform, media files you privately shared within direct messages or Twitter data archive downloads could have been stored within the browser's cache.

This means that threat actors could have stolen your private data using malicious tools designed to go through Firefox's cache, while anyone could have got their hands on your personal information if you ever logged in on Twitter from a public computer.

"We recently learned that the way Mozilla Firefox stores cached data may have resulted in non-public information being inadvertently stored in the browser's cache," Twitter said.

"This means that if you accessed Twitter from a shared or public computer via Mozilla Firefox and took actions like downloading your Twitter data archive or sending or receiving media via Direct Message, this information may have been stored in the browser’s cache even after you logged out of Twitter."

Luckily, the private data stored by Firefox within its cache is automatically being removed after the browser’s default cache retention period of 7 days is reached, with all the accidentally stored private info also being deleted in the process.

Users of other web browsers such as Google Chrome and Safari were not affected by this issue according to the social networking giant.

Twitter says that it has made a change to its platform that will prevent Firefox from caching users' personal information going forward.

"If you use, or have used, a public or shared computer to access Twitter, we encourage you to clear the browser cache before logging out, and to be cautious about the personal information you download on a computer that other people use," Twitter adds.

To clear Mozilla Firefox's cache, you have to click the menu button and go to Options > Privacy & Security > Cookies and Site Data > Clear Data.

There you have to uncheck the Cookies and Site Data option and only check Cached Web Content (as shown above) and then click the Clear button. 

"We’re very sorry this happened. We recognize and appreciate the trust you place in us, and are committed to earning that trust every day," Twitter concluded.

"If you have any questions or concerns regarding this incident, you can contact Twitter’s Data Protection Officer by completing the online form located here."

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