The AntiSec movement was one of the last public cause statements issued by the LulzSec hacktivist group before it disbanded over the weekend, Infosecurity notes.
MasterCard isn't commenting on the DDoS attack, but some news wire reports suggest that access to the site was intermittent in some areas of the world, notably the US and UK, for several hours yesterday.
What is interesting, however, is that the site was accessible in some areas of Europe when it was apparently being DDoS-ed in the US and UK, suggesting that the IP route diversification that MasterCard said it was deploying following previous attacks may have worked.
According to the Softpedia news wire, a hacker using the name Ibom Hacktivist posted messages on the Twitter microblogging services yesterday, attributing the DDoS attacks to the WikiLeaks cause.
The East European news wire also asserts that five people, two of whom are minors, have been detained in the UK over the DDoS attacks, along with a 16-year-old in the Netherlands. Other reports, meanwhile, suggest that similar arrests are taking place in the US.
According to Graham Cluley, senior technology consultant with Sophos, whatever your personal objections to a company, the DDoS attacks are still illegal and those responsible can face prosecution.
"We've seen plenty of headlines over the past couple of months about high profile hacking incidents and unfortunately, the momentum doesn't seem to be slowing", he said.
"This means that the risks to internet users aren't going away and attacks like this should be a wake-up call for us all when it comes to internet security" he added.
Cluley went on to say that, whilst there's obviously a vast contrast between DDoS attacks and the bad guys looking to steal sensitive information for financial gain, the biggest concern is the attitude towards these attacks, with hackers portraying that it's all a bit of fun.
"Companies and computer users mustn't sit back and laugh along, thinking that these attacks won't affect them. Businesses need to be sure of the quality of their security systems and all of us who entrust our sensitive information to third parties should be aware that the problem could affect us too", he said in his security blog.