Jun 24, 2011 16:41 GMT  ·  By

NATO has warned users of its e-Bookshop site that their data might have been stolen during a recent attack against carried out by unknown perpetrators.

"Police dealing with digital crimes have notified NATO of a probable data breach from a NATO-related website operated by an external company.

"NATO’s e-Bookshop is a separate service for the public for the release of NATO information and does not contain any classified data. Access to the site has been blocked and subscribers have been notified," the alliance announced.

The NATO e-Bookshop site provides users with access to the alliance's publications in digital and printed formats. It's not immediately clear if the NATO attack is related to the new Anti-Security campaign launched by LulzSec.

Late last week the infamous hacking group called on everyone to attack online governmental assets as a form of protest. Some hacking outfits have joined the campaign while others positioned themselves against it.

A group of Brazilian hackers began hitting their country's government websites, while LulzSec hacked into Arizona Department of Public Safety computers and leaked confidential data taken from them.

The group noted that more information will be released on Monday, but have made no reference to NATO, so it's not clear if the upcoming release is related to this incident.

In a report about national security issues drafted earlier this month, NATO's general rapporteur presented Anonymous as a threat.

"Today, the ad hoc international group of hackers and activists is said to have thousands of operatives and has no set rules or membership. It remains to be seen how much time Anonymous has for pursuing such paths.

"The longer these attacks persist the more likely countermeasures will be developed, implemented, the groups will be infiltrated and perpetrators persecuted," he wrote.

Just this week, a former Anonymous member who was also loosely affiliated with LulzSec, was arrested in the UK and charged with offenses under the Computer Misuse Act.