The NSA is not sure what secret national security documents Edward Snowden accessed, NBC News reports.
Snowden used his security clearance as a NSA contractor to download 20,000 documents.
The NSA currently has an ongoing investigation into which high-level officials Snowden impersonated in order to obtain the documents. It is restricting its investigation to individuals with access to sensitive documents.
The NSA has already identified several instances where Snowden borrowed someone else’s user profile to access documents, said the official.
Each user profile on NSAnet includes a level of security clearance that determines what files the user can access. Like most NSA employees and contractors, Snowden had a "top secret" security clearance, meaning that under his own user profile he could access many classified documents. But some higher level NSA officials have higher levels of clearance that give them access to the most sensitive documents. […]
As a system administrator, according to intelligence officials, Snowden had the ability to create and modify user profiles for employees and contractors. He also had the ability to access NSAnet using those user profiles, meaning he could impersonate other users in order to access files. He borrowed the identities of users with higher level security clearances to grab sensitive documents.
Once Snowden had collected documents, his job description also gave him a right forbidden to other NSA employees– the right to download files from his computer to an external storage device.
A former intelligence official told NBC News, "The damage, on a scale of 1 to 10, is a 12."