Gen. Alexander, in testimony before the House Permanent Select Committee on Intelligence, said Tuesday that NSA has about 1,000 computer systems administrators at its worldwide network of listening posts and other facilities.
The four-star general was asked how many NSA systems administrators had the same access to agency secrets as Mr. Snowden, who disclosed top-secret surveillance programs to the news media and who is now in hiding in Hong Kong.
“There is on the order of 1,000 system administrators — people who actually run the networks — who have, in certain sections, that level of authority and ability to interface with the systems,” Gen. Alexander said. “The majority are contractors.
“We do have significant concerns in this area, and it is something that we need to look at.
“The mistakes of one contractor should not tarnish all the contractors because they do great work for our nation as well,” Gen. Alexander said.
Since the disclosures, NSA technology directorate plans to adopt a two-member control system that will prevent a single system administrator from making any changes to networks, he added.
NSA decided about 13 years ago to downsize its workforce.
“We pushed more of our information technology workforce or system administrators to the contract arena,” he said. “That’s consistent across the intelligence community.”
Gen. Alexander said systems administrators have access to computer systems and are “helping to run the network and the Web service that are on that network that are publicly available.”
“To get to any data like the business records 215 data that we’re talking about, that’s in an exceptionally controlled area,” he said, referring to Section 215 of the USA Patriot Act.
“You would have to have specific certificates to get into that. I am not aware that Snowden had any access to that.”
Each type of sensitive or classified data needs “certificates” that require physical presence as opposed to remote access via computer, something that would be “extremely difficult” for Mr. Snowden, Gen. Alexander said.
Disclosures by Mr. Snowden so far have revealed NSA’s Prism program to spy on major data companies’ information, the court order to Verizon for its phone metadata and a classified presidential directive on cyberwarfare.
Federal investigators are trying to determine how Mr. Snowden, as an NSA systems administrator, was able to access such closely guarded secret documents, raising questions about his potential hacking into classified computer networks.