As expected, Christmas has shown to have had gamers worried at the security of their accounts- though not at the hands of the Xbox Live or Playstation Network hackers that were expected. Probably ALL users of Steam have been affected by Steam’s current flaw.
At first glance, some users have noticed that their store homepage is in a different language or currency (Personally, I have had my store displayed in Russian Rubles and US Dollars). More seriously, if users go into their account details by pressing their steam name in the top right of the client, the page takes you to another user’s account details.
While it hasn’t been confirmed to be hackers, this Steam issue is something that needs to be taken seriously. Any user is able to access your account’s email address, Steam Wallet balance, and purchase history, among other things.
“By the way, this is not a security breach. This is a page caching gone rogue. Most likely not respecting Cache-Control headers.” -@SteamDB on Twitter.
To help secure your account, use Steam Guard and the Mobile Authenticator, account details that I’ve had access to have been equipped with one or the other of these precautions.
It still seems strange that Valve haven’t yet taken any drastic action into preventing further damage, as, well.. accounts are in danger here.
For more information, see SteamDB on Twitter. There is also a Megathread on Reddit right now regarding the issue.