The world’s largest Bitcoin exchange Mt. Gox has once again been hit by a distributed denial of service (DDoS) attack. At the time of writing, the site has been down for over three hours, as the company scrambles to fight back.

On Facebook and Twitter, the company first informed its users that it was experiencing an outage and then later followed up to confirm the source was indeed yet another DDoS attack. Since the Facebook posts naturally offer more details, they’re the ones worth quoting, and especially so as the site doesn’t exactly offer a friendly error message:

mtgox down1 Here we go again: Top Bitcoin exchange Mt. Gox taken down for hours by another strong DDoS attack (Updated)

Here’s the first one, posted at 10:43 AM EST:

We are experiencing some downtime at the moment and are investigating the source. Will update once the issue is clarified or resolved. Apologies for the temporary inconvenience.

The second one was published at 12:49 PM EST:

UPDATE: This again appears to be another strong DDos attack. We are working hard to overcome it and will update when possible. It’s currently 2am in Japan so please forgive us if our Facebook/Twitter updates are not as quick, though the team is certainly not taking any breaks. We’re very much looking forward to implementing a much stronger solution very soon and will make an announcement to that effect once it’s in place.

Over at Bitcoinity, we can see that the last trade on Mt. Gox was for $125.03. Given its size, Bitcoin’s value is likely to plummet again once the site reopens, followed by an eventual rebound.

Bitcoin fluctuates wildly as it is, but it is particularly dependent on Mt. Gox as the exchange is the world’s largest (last week’s series of events was a prime example). Many believe those behind the DDoS attacks are performing them to drop the digital currency’s valuation so they can buy low and sell high, before doing it all over again.

Depending on which exchange you trust, here’s the current situation (numbers courtesy of Bitcoin Watch):

btceUSD – $104.94
bitstampUSD – $112.69
cbxUSD – $111.11

We’ll keep you posted as we learn more.

Update at 2:50 PM EST – The site is now giving spitting out the following message: “Database access error, please retry later.” We’re not sure, but this would suggest the DDoS attack is being mitigated successfully and the site may come back soon.

Update at 3:00 PM EST – We’re seeing the site cycling between loading properly and the above two errors. This one’s not over yet folks, but we will let you know when the service appears to be back.

Update at 3:45 PM EST – Although Mt. Gox has not confirmed on Facebook nor on Twitter, the service appears to be back (DownForEveryoneOrJustMe agrees as well). The site is loading reliably for us and trading has resumed. This particular outage lasted about five hours.