NSA using Google's online ad tracking tools to spy on web users

Android and Apple smartphones also tracked using app location tools

The US National Security Agency (NSA) and GCHQ are using Google cookies and other tools used by internet advertisers to spy on web users around the world.

The slides leaked by whistleblower Edward Snowden show that "when companies follow consumers on the internet to better serve them advertising, the technique opens the door for similar tracking by the government. The slides also suggest that the agency is using these tracking techniques to help identify targets for offensive hacking operations".

The web-tracking tools are being surreptitiously used to identify targets. "The intelligence agencies have found particular use for a Google-specific tracking cookie known as the 'PREF-ID'. These cookies typically don't contain personal information, but they do contain numeric codes that enable websites to uniquely identify a person's browser," claims the Washington Post, the newspaper that broke this latest Snowden story.

It continues: "In addition to tracking web visits, this cookie allows the agencies to single out an individual's communications among the sea of internet data in order to send out software that can hack that person's computer."

The NSA uses advertising cookies to home in on someone already under suspicion, according to the slides.

It is also using the tracking capabilities of modern smartphones and the apps they run to identify and locate targets.

"Many smartphone apps running on iPhones and Android devices, and the Apple and Google operating systems themselves, track the location of each device, often without a clear warning to the phone's owner. This information is more specific than the broader location data the government is collecting from cellular phone networks."

However, the slides do not identify how the agencies are using these cookies and commercial tracking techniques for their own ends.

Furthermore, Google - original motto: 'Don't be evil' - has declined to comment on the allegations.