A spin-off group of cyber hacker collective Anonymous have published 90,000 military email addresses and passwords stolen from a large US contractor.
The group claims it broke into the servers of technology contractor Booz Allen Hamilton and stole the login details. Anyone can download the details, which have been published on BitTorrent file sharing sites.
eWeek said the information available to download includes "login information of personnel from US CENTCOM, SOCOM, the Marine Corps, Air Force facilities, Department of Homeland Security, Department of State and other private sector contractors."
The hacking collective dubbed the operation "military meltdown Monday.”
"We infiltrated a server on their network that basically had no security measures in place," Anonymous said online.
Chris Palmer of the Electronic Frontier Foundation told CBS News that those exposed by the leak "should probably be changing their passwords urgently."
Booz Allen posted a message on Twitter shortly after the hack was announced, saying that its security policy meant it didn't usually comment on threats or attacks against its systems.
The hackers mocked the company in response."You have a security policy?" they said. "We never noticed."
The Pentagon said it was aware of the incident and was coordinating with other federal agencies.
Anonymous have targeted government contractors in the past week, breaking into the system of another US government contractor, IRC Federal, which does work for the FBI and the military. The contractor's website was defaced and documents and emails were stolen from its internal databases.