NSA whistleblower Edward Snowden is believed to have used a 'thumb-sized' USB data storage device which is banned from use in intelligence agencies, for breaching the military networks and attaining the Top Secret documents.
The 'thumb-sized' USB device is banned from the military networks because such a use had earlier infected the US Central Command with malicious software thought to be of Russian origin, Washington Times reports.
According to the report, Snowden is believed to have deactivated the alarm bells before breaching the codes and exceeding his access to the secret intelligence.
House Permanent Select Committee on Intelligence Chairman Michael Rogers, said that investigation is on regarding how much Snowden exceeded in his access and how much of secret intelligence data lies with him.
Rogers further said that even at top secret level one can surf around and lots of secret documents are routinely posted without any additional access controls, beyond the fact that are on a highly classified network to which only cleared personnel have access, adding that NSA too would have suffered from such a system, the report added.
