NSA whistleblower Edward Snowden has just revealed that the US is developing a cyber-warfare program that would not only defend the country from foreign attacks, but also launch retaliatory campaigns against hackers.

The new system, called MonsterMind, is the latest in a string of revelations attributed to Snowden, who first rose to notoriety last year for handing over classified information to journalists.

In an interview with Wired, Snowden said that the technology is autonomous, and can instantly neutralize cyber-attacks launched by foreign hackers. The program is said to have the capability to analyze large amounts of metadata to determine normal Internet traffic from malicious traffic. When it identifies a traffic pattern as an attack, it would automatically block or "kill" it before it enters the country. The interview, one of Snowden's most extensive to date, reveals the system for the first time. 

"If you have hundreds or thousands of flows starting up from a particular place and targeted to a particular machine, this might indicate you're under attack. That's how intrusion detection and anomaly-detection systems generally work," Matt Blaze, a computer science associate professor from the University of Pennsylvania, told Wired. 

While there are similar cyber-defense programs in existence, Monstermind is unique because it would have the capability to launch retaliatory attacks against hackers. The system, which would automatically fire back without human supervision, is said to be problematic because such attacks are route through innocent countries. For instance, a hacker that launched an attack from China can make it look like the malicious traffic came from Russia. 

"The argument is that the only way we can identify these malicious traffic flows and respond to them is if we're analyzing all traffic flows," Snowden said. "And if we're analyzing all traffic flows, that means we have to be intercepting all traffic flows. That means violating the Fourth Amendment, seizing private communications without a warrant, without probable cause or even a suspicion of wrongdoing. For everyone, all the time."

Snowden said that running such an autonomous program runs the risk of accidentally starting a war. He said that the MonsterMind program was part of the reason why he decided to leak sensitive American intelligence data to the press.