The US Federal Reserve has admitted that it was hacked during Sunday's Super Bowl, with hacktivist group Anonymous stepping forward to claim responsibility.
The Fed said that no lasting damage was done, with nothing of value accessed or stolen.
A couple of days earlier, a Twitter feed purporting to belong to Anonymous members, claimed that the hactivist collective had hacked into government systems and accessed the personal details of more than 4,000 US bankers. It published those details on the web.
"The Federal Reserve system is aware that information was obtained by exploiting a temporary vulnerability in a website vendor product," a Fed spokeswoman told Reuters.
"Exposure was fixed shortly after discovery and is no longer an issue. This incident did not affect critical operations of the Federal Reserve system," the spokeswoman added, stating that all individuals affected by the breach had been contacted.
The breach is thought to be part of 'Operation Last Resort', launched by Anonymous members in January aiming to take on government web sites after the suicide of internet activist Aaron Swartz, who was facing prosecution for breaking into servers belonging to the Massachusetts Institute of Technology, and posting academic articles from JSTOR (Journal Storage) without permission.
Last month, the US Sentencing Commission Web site was breached in protest over the Swartz case.
Although doubts persist over the nature of the data accessed by Anonymous - with the hacktivists claiming to have usernames, passwords and IP addresses, and the Federal Reserve claiming otherwise - the breach raises serious doubts over the security of the Fed's systems.