Both enlisted in the Army during the war in Iraq only to later say they were disillusioned by that conflict. Neither has a college degree or extensive academic training in computer science. And yet both were technically savvy, able to navigate sensitive computer networks and smuggle classified files.
The back-to-back breaches — seen by many as the most significant in decades — have forced U.S. intelligence officials to examine whether the cases are isolated in scope or part of a new category of exposure emerging at the edges of classified U.S. networks.
U.S. officials said counterintelligence teams are already looking beyond the details of the Snowden case at any vulnerabilities it has exposed.
“At this point, we’re still looking at this as an anomaly,” a senior U.S. intelligence official said. But he said a damage assessment ordered by Director of National Intelligence James R. Clapper Jr. is broad in scope, focused largely on the implications of a case in which highly sensitive materials were somehow within the grasp of a contractor who moved through a series of low-ranking jobs for the CIA and the NSA.
Snowden and Manning both took advantage of access to computer systems that expanded exponentially in the aftermath of the attacks of Sept. 11, 2001, partly in an effort to make critical information available across agencies.
Since the disclosures by WikiLeaks in 2010, the Pentagon has taken steps to better protect its classified networks. It has banned the use of thumb drives unless special permission is given, mandated that users have special smart cards that authenticate their identities and required analysts to review computer logs to identify suspicious behavior on the network.
Despite such measures, it remains impossible to guarantee security on any classified network. Since going public, Snowden has attributed his extensive access to his role as an ordinary systems administrator for the NSA, although he offered few specific details about where he found or how he removed such sensitive files.
In an e-mail to a Washington Post reporter last month, he said he wanted “to embolden others to step forward,” suggesting that he hoped his leak would trigger follow-up disclosures.
Among the files he obtained were a secret order issued by the Foreign Intelligence Surveillance Court and 41 briefing slides on a highly classified program, called PRISM, in which mainstream technology companies including Microsoft, Google and Facebook have given the NSA extensive access to e-mails, videos and other content.