Update 19.00 GMT: Steam appears to back online and back to normal.
Update 18.45 GMT: It looks like Steam is beginning to recover with some service to the Steam servers being restored. At present the Steam Store and most of the Steam Community features still appear to be down.
Check https://steamstat.us/ to stay updated
Update 17.50 GMT: Phantom Squad have claimed responsibility for knocking Steam servers offline, meaning that a DDOS attack may have been the reason Steam went down. It appears that it is not just Phantom Squad who are attacking the servers, however, with numerous different groups and people also claiming to have taken part.
— Phantom Squad (@PhantomNations) December 23, 2016
Original Story: As if by tradition, Steam has been knocked offline once again at Christmas following what appears to be a possible DDOS attack. Steam currently appears to be down for everyone in all regions with all functionality also being offline including the Steam Store, Steam Community, and Steam WebAPI according to SteamStatus.
Steam’s usual maintenance time is on a Tuesday, so it is unlikely that the current downtime is due to that, especially as Valve would announce if they had to do emergency maintenance and had to bring the servers down. Despite the Steam sale being extremely popular and seeing more people head over to Steam’s servers than normal, it’s unlikely that is the cause of the servers being down as the sale began yesterday and did not go down when there would have initially been the highest volume of traffic at the start of the sale.
That means a DDOS attack could be a plausible explanation at the moment. On Twitter various ‘hacking’ groups have hinted at launching large attacks over Christmas, although none of them have so far come out and claimed responsibility for taking Steam offline.
Last Christmas Steam totally collapsed due to an internal error which saw different users’ personal information appear on other people’s accounts. Steam was also offline for the majority of Christmas day before the issue finally got resolved. According to Valve, it was an error and not the result of a hack which caused the disruption. Until we hear from Valve directly, it could also be another internal error which has taken Steam offline considering that everything is down. In a DDOS attack it doesn’t always take absolutely everything offline, and some users can still find themselves able to connect. That doesn’t seem to be the case, as we haven’t been able to find anyone who has remained connected.
Unfortunately, every Christmas seems to see gaming’s three major online services being the victims of DDOS attacks with Steam, Xbox Live and PSN all being knocked offline at various points throughout the festive period for the last few years.
As of yet there’s been no official comment by Valve, but it’s likely they will comment on Steam being down shortly and will try to restore service as usual as soon as possible.