Steam users, logging in to check and download PC games for Steam Winter Sale 2015, were shocked to see the home page being set in different language and account information including credit card details, billing address and purchase history and emails of other users on their page.
Valve, which owns and operates Steam had to act quickly. So it shut down the Steam Store for some time as it was fixing this issue.
Following this, it put up a post saying that the Steam Store was back online and it had resolved the security issue that was blamed on caching misconfiguration in one of the components.
"Steam is back up and running without any known issues. As a result of a configuration change earlier today, a caching issue allowed some users to randomly see pages generated for other users for a period of less than an hour. This issue has since been resolved. We believe no unauthorized actions were allowed on accounts beyond the viewing of cached page information and no additional action is required by users," said Valve spokesperson to GameSpot.
It is not clear how many users were affected by this security error. And Valve confirmed in the blog post that "this was not a hack or a DDoS attack".
Valve also cautioned players not to store their billing information on Steam Store. It also advised Steam users to unlink their PayPal account in case they have it saved.
Eurogamer reported that there were no new purchases that could be made during the scare in spite of users being able to see details of others' accounts.