These 4 countries are the biggest threats to US cybersecurity

Securing digital infrastructure is becoming more of a national priority, and intelligence agencies are taking notice.

The US's director of national intelligence, James Clapper, delivered a report to the Senate last week, where he detailed what he saw as the future of global cyberwarfare.

Clapper noted he does not foresee a "catastrophic attacker" happening anytime soon. He instead believes the future to be "an ongoing series of low-to-moderate level cyber attacks."

He went on to name the biggest perpetrators of these assaults:

• China is perhaps one of the most prevalent sources of cyberattacks. This was evidenced last weekend by a prolonged offensive against the US-based code repository GitHub, which stemmed from "certain devices at the border of China's inner network." Clapper added while Chinese attacks are prevalent, its hackers often use "less sophisticated cyber tools to access targets."
• Russia may be of more concern, however. The country is reportedly building out its own cyber command, which "will be responsible for conduction offensive cyber activities, including propaganda operations and inserting malware into enemy command and control systems." While China's attacks may be more frequent, Russia is looking to up its game and launch more nefarious and advanced hacking programs.
• Iran is another country the US is focusing on as a potential target of cyberwarfare. The report noted Iran was implicated as the source of a series of DDoS attacks that targeted US financial institutions in 2012 and 2013.
• North Korea may be the most notorious cyber attacker following last year's Sony hack. The Sony debacle is by far the most advanced action the country has taken against another regime, but Clapper noted that it "uses its cyber capabilities for political objectives."

Clapper also described a potential inflection point in cyber tactics. Up until now, attacks have focused on either destroying an infrastructure entirely or gaining access to private information. "In the future," Clapper wrote, "we might also see more cyber operations that will change or manipulate electronic information in order to compromise its integrity."

This means hackers may launch more clandestine cyber-espionage programs that gain access to data and slightly alter it so victims lose credibility. This could lead to executives and government officials alike losing trust in the digital information they access.

In short, cyberwarfare is a modern reality. Countries now are seeking out hackers to pursue digital espionage programs. What countries must do now, according to Clapper, is not try to eliminate cyber threats but more actively manage potential risks.