The site suffered a Distributed Denial of Sevice (DDoS) attack on Tuesday and Wednesday, according to the BBC, though the site administrator, under the username Dread Pirate Roberts, has now confirmed the site is back in service.
"Silk Road is open and accessible. As soon as the attacker finds out, he will likely change his tactics and try to take the site down again. Hopefully he won't be able to, but time will tell," he said.
The online black market was launched in February 2011 and has been accused of selling tainted goods. US legislators have called for its closure.
As of March 2013 10,000 products were listed for sale, 70 per cent of which were 340 varieties of drugs. Other goods and services available include art, books, jewellery, pornography and writing services, with estimated annual sales of US$15 million.
The site does however restrict the sale of child pornography, stolen credit cards, assassinations and weapons of mass production, which fall out of its terms of service, which prohibit sales of "anything whose purpose is to harm or defraud."
The BBC reports that prior to the site’s recovery owners feared the attack could have exposed the vulnerabilities of the Tor network, which grants anonymity to online users, making it attractive to people involved in underhand deals as well as political activists.
It remains unclear as to who could be behind the attack, with business competitors looking to set up a rival site while government interference cannot be ruled out.
The site was one of the early adopters of the use of Bitcoins to carry out transactions, due to the nature of anonymity needed.