LulzSec, which has breached the IT systems at Sony and Fox News, and issued warnings of weaknesses at Nintendo and the NHS, said it had carried out the attack for fun, according to numerous reports.
Senate officials confirmed that there is no individual user account information on the server supporting senate.gov that could have been compromised.
LulzSec posted files online that indicated it had been in the Senate network, but none of the files contained sensitive information.
"Although this intrusion is inconvenient, it does not compromise the security of the Senate’s network, its members or staff", said Senate Deputy Sergeant at Arms Martina Bradford in a press release statement. "Specifically, there is no individual user account information on the server supporting senate.gov that could have been compromised.”
According to a report by Politico, the Senate's Sergeant at Arms has ordered "a review of all the sites hosted on senate.gov" and is "urging the individuals responsible for those sites to conduct their own review."
The problem with security on senate.gov, noted the political news site, is that each member of the chamber is responsible for maintaining their own site on the domain, and as Bradford added, they "may not always incorporate recommended security protocols."
This was not the first time a hacker group attacked a Congressional website. In February 2010, the alleged Brazil-based Red Eye Crew hacked the websites of 49 House members just after the president's state of the union address.
Portions of this article were first published by Computer Weekly