Snowden suspected of covering electronic tracks

The IS government has been trying to determine which highly classified material Snowden took from the NSA

The US government's efforts to determine which highly classified materials leaker Edward Snowden took from the National Security Agency have been frustrated by Snowden's sophisticated efforts to cover his digital trail by deleting or bypassing electronic logs, government officials said. Such logs would have showed what information Snowden viewed or downloaded.

The government's forensic investigation is wrestling with Snowden's apparent ability to defeat safeguards established to monitor and deter people looking at information without proper permission, said the officials, who spoke on condition of anonymity because they weren't authorised to discuss the sensitive developments publicly.

In July, nearly two months after Snowden's earliest disclosures, NSA Director Keith Alexander declined to say whether he had a good idea of what Snowden had downloaded or how many NSA files Snowden had taken with him, noting an ongoing criminal investigation.

The disclosure undermines the Obama administration's assurances to Congress and the public that the NSA surveillance programs can't be abused because its spying systems are so aggressively monitored and audited for oversight purposes: If Snowden could defeat the NSA's own tripwires and internal burglar alarms, how many other employees or contractors could do the same?

NSA spokeswoman Vanee Vines told the AP that Alexander "had a sense of what documents and information had been taken," but "he did not say the comprehensive investigation had been completed." Vines would not say whether Snowden had found a way to view and download the documents he took, without the NSA knowing.

In defending the NSA surveillance programs that Snowden revealed, Deputy Attorney General James Cole told Congress last month that the administration effectively monitors the activities of employees using them.

"This program goes under careful audit," Cole said.

"Everything that is done under it is documented and reviewed before the decision is made and reviewed again after these decisions are made to make sure that nobody has done the things that you're concerned about happening."

The disclosure of Snowden's hacking prowess inside the NSA also could dramatically increase the perceived value of his knowledge to foreign governments, which would presumably be eager to learn any counter-detection techniques that could be exploited against US government networks.

It also helps explain the recent seizure in Britain of digital files belonging to David Miranda the partner of Guardian journalist Glenn Greenwald in an effort to help quantify Snowden's leak of classified material to the Guardian newspaper. Authorities there stopped Miranda last weekend as he changed planes at Heathrow Airport while returning home to Brazil from Germany, where Miranda had met with Laura Poitras, a US filmmaker who has worked with Greenwald on the NSA story.