34,000 gamers affected by Christmas attack on Steam

Steam set a new record on Jan. 3 when over 12 million gamers were all gaming at the same time. Gamasutra reported that there were 12,332,504 concurrent users. The Steam stats showed Dota 2 as the most played game which peaked at 940,373 concurrent gamers. Counter-Strike had 643,402 concurrent players and Fallout 4 came in third at the peak with 116,599 gamers. That being said, today is the last day of the Steam winter sale.

Of the millions of gamers buying and playing games over their holiday break, how many were aware of the Christmas day attack on Steam? If you were hunting for a new game when it happened, then you probably knew about it as Steam was up, down, and even accidentally shared the personal details of about 34,000 gamers.

On Christmas day, some gamers visiting the Steam Store during the Winter Sale were bewildered by their Steam client showing Russian or another language different than their own. Concerned, some players who checked out their account settings saw other people’s personal details such as partial credit card numbers, phone numbers and email addresses. A bit later, Valve shut down the Steam Store altogether…but users were left in the dark about what happened.

After five days of silence, Valve finally explained “Steam’s troubled Christmas” that resulted in strangers viewing about 34,000 Steam users’ sensitive information. The personal details served up to other players “varied,” but ranged from Steam users’ “billing address, the last four digits of their Steam Guard phone number, their purchase history, the last two digits of their credit card number, and/or their email address.” Valve added, “These cached requests did not include full credit card numbers, user passwords, or enough data to allow logging in as or completing a transaction as another user.”

Perhaps that makes you feel better, but as ExtremeTech’s seemingly annoyed Joel Hruska wrote:

Imagine that you use three different services, all of which are hacked. Hack #1 exposed your username and an encrypted form of password that can be cracked with sufficient effort. Hack #2 leaks your billing address, while Hack #3 leaked credit card information and a name associated with the account. Individually, all three are annoying. Combine them, and an attacker can do serious harm. Given that we’ve seen large corporations wait weeks or months before disclosing the extent of a data breach, it’s possible for your personal data to be compromised long before you’re aware to even look for a problem.

The Next Web previously reported that “77,000 Steam users are hacked every month.” In the past, Valve admitted that Steam Trading had increased its security problems “twenty-fold,” before urging gamers to uses its two-faction authentication solution, Steam Guard Mobile Authenticator. But that wasn’t enough to protect gamers during the Christmas day attacks; Wired reported, “Even players using the Steam Guard authenticator to log in were affected, their details offered up as readily — if randomly — as anyone else’s despite the authenticator’s entire purpose being to protect accounts.”

Valve, attempting to reassure gamers after having zipped lips on the attack for nearly a week, said it would contact users who were affected after those players have been identified. As for how it happened, Valve wrote:

Early Christmas morning (Pacific Standard Time), the Steam Store was the target of a DoS attack which prevented the serving of store pages to users. Attacks against the Steam Store, and Steam in general, are a regular occurrence that Valve handles both directly and with the help of partner companies, and typically do not impact Steam users. During the Christmas attack, traffic to the Steam store increased 2000% over the average traffic during the Steam Sale.

In response to this specific attack, caching rules managed by a Steam web caching partner were deployed in order to both minimize the impact on Steam Store servers and continue to route legitimate user traffic. During the second wave of this attack, a second caching configuration was deployed that incorrectly cached web traffic for authenticated users. This configuration error resulted in some users seeing Steam Store responses which were generated for other users. Incorrect Store responses varied from users seeing the front page of the Store displayed in the wrong language, to seeing the account page of another user.

Once this error was identified, the Steam Store was shut down and a new caching configuration was deployed. The Steam Store remained down until we had reviewed all caching configurations, and we received confirmation that the latest configurations had been deployed to all partner servers and that all cached data on edge servers had been purged.

In closing, Valve promised to keep working to identify affected gamers as well as “to improve the process used to set caching rules.” Valve added, “We apologize to everyone whose personal information was exposed by this error, and for interruption of Steam Store service.”