When we heard about this the other day we were like oh boy not again. At the time though, it seemed to be isolated to just the Steam forums but Valve has just released an email to the Steam user base alerting them that it is much more serious than that. According to Valve, the intruders also gained access to a Steam database in addition to the forums. This database contained information including user names, hashed and salted passwords, game purchases, email addresses, billing addresses and encrypted credit card information. Currently, they do not have evidence that encrypted credit card numbers or personally identifying information were taken by the intruders, or that the protection on credit card numbers or passwords was cracked. They are not sure though and are still investigating. Even though they say they don’t have any evidence of credit card misuse at this time they recommend you watch your credit card activity and statements closely.
To this point they only know of a few forum accounts that have been compromised. Once the forums are back online, all forum users will be required to change their passwords the next time they login. If you have used your Steam forum password on other accounts you should change those passwords as well.
At this point they aren’t aware of any know of any compromised Steam accounts, so we are not planning to force a change of Steam account passwords (which are separate from forum passwords). However, it wouldn’t be a bad idea to change that as well, especially if it is the same as your Steam forum account password.
Valve hopes to reopen the forums soon but they haven’t given any specifics as of yet.