It appears that the Steam community site suffered from an exploit involving user profiles that could redirect users to alternate pages and download PHP code, Ars Technica reports. Valve was able to fix the exploit soon after it was announced, but not before a number of people had created profiles that exploited the vulnerability.
The exploit was first identified on the Steam subreddit, described as such:
“Currently, there is a risk (i.e. phishing, malicious script execution, etc.) involved when viewing or simply opening PROFILE pages of other steam users as well as your OWN activity feed (both desktop and mobile versions on all browsers including steam browser/chromium). I would advise against viewing suspicious profiles until further notice and disable JavaScript in your browser options. Do NOT click suspicious (real) steam profile links and Disable JavaScript on Browser. Appropriate information has been forward to Valve and this issue should be resolved soon, sorry for any inconvenience.”
Since that post was first created, Valve was able to fix the exploit and was able to classify Steam profiles and activity feeds as safe to visit. The exploit was subsequently explained in full in a follow-up Reddit post. Steam has more than 125 million users and any exploit on the Steam community site could have serious repercussions.
Apparently, the chances of long-term problems caused by the vulnerability were slim, but nevertheless, anyone who might have suffered from the exploit while it was live is recommended to turn on two-factor authentication, keep up with Valve’s official channels for more information, and, of course, change their Steam password.
