U.S. discloses zero-day exploitation practices

The federal government has confirmed that it uses undisclosed software bugs not only in espionage and intelligence gathering, but also in the course of law enforcement activities.

In November 2015, the government released a redacted version of the Vulnerabilities Equities Process, the policy that lets agencies such as the National Security Agency and FBI decide whether to announce the flaws to vendors for patching. Just weeks ago, the government argued that acknowledging its exploitation of the software flaws, known as zero-day vulnerabilities, would damage national security.

Now the government has rescinded some of those redactions in its first official acknowledgment of "defensive, offensive and/or law enforcement-related [and] prosecutorial" uses of the vulnerabilities beyond counterterrorism efforts. The disclosure comes in response to a Freedom of Information Act lawsuit filed by the Electronic Frontier Foundation seeking the release of documents on the U.S. government's use of such flaws for intelligence gathering.

"This is the first confirmation that [the Vulnerabilities Equities Process] is used for law enforcement, which was an open secret," said EFF staff attorney Andrew Crocker. The surveillance isn't used for "just national security or intelligence gathering."

The government has long been suspected of discovering and stockpiling flaws in commercial code to gather information for potential use in cyber warfare, although the government has denied doing so.

If alerted to the existence of the vulnerabilities, software companies could quickly create a security patch. However, by not alerting developers, government agencies leave the vulnerabilities open for their own covert access -- and potentially for any malefactors capable of exploiting the flaws. That means the government must choose between protecting its surveillance access and protecting U.S. software against hacking, which can have "far-reaching consequences for both information security and user privacy," according to EFF's FOIA request.

The less-redacted document also discloses the government's policy for deciding what to do when a vulnerability is discovered. NSA is supposed to report the vulnerability to the company unless there is "a clear national security or law enforcement" reason not to. The decision about whether and what to publicize is solely at the agencies' discretion.

Furthermore, although the process was finalized in 2010, it was not effectively implemented, which led to a 2013 presidential review board's recommendation "to prioritize disclosure over offensive hacking."

The remaining redacted information likely includes which agencies have been involved in discussions about zero-day disclosures, according to EFF. The government is still withholding that information in the name of national security. EFF has a February court date to contest that claim.