All Bitcoins stored at the Silk Road 2.0 hidden marketplace have been stolen. According to the operator of the marketplace, they were stolen through a vulnerability in the Bitcoin protocol, but those involved doubt that.
The theft used transaction malleability, a vulnerability in the Bitcoin protocol, claims the operator of the Silk Road 2.0 marketplace on the Bitcointalk forum. Silk Road 2.0 was created after the FBI closed the original Silk Road and arrested its owner.
Other visitors to the Bitcointalk forum take the administrator’s statement with a grain of salt, as adversaries cannot exploit the transaction malleability vulnerability to steal Bitcoins, only to prevent confirmation of transactions. This makes the attack a denial of service.
Users of the site therefore suspect that the administrator himself ran off with the money, or that the Bitcoins were stolen in some other way. It is not known how many Bitcoins were stored at Silk Road 2.0; a researcher tells Forbes that there are an estimated 4400. They thus represent a value of 1.3 million euros. Since the emergence of the transaction malleability vulnerability, the value of the cryptocurrency has fallen sharply in a short time, as Bitcoin exchanges such as Mt.Gox temporarily do not pay out.