Suspected Chinese hackers breach more US defense and tech firms ::

— A suspected Chinese hacking campaign has breached four more US defense and technology companies in the last month, and hundreds more US organizations are running the type of vulnerable software that the attackers have exploited, according to research shared with CNN.

The apparent espionage activity, which the National Security Agency helped investigate when it emerged in recent months, is more extensive than previously known and has seen the hackers steal passwords from targeted organizations with a goal of intercepting sensitive communications.

The cybersecurity researchers in November publicly confirmed just one victimized US organization, CNN reported then, but they now say the number is five and could continue to grow.

Globally, at least 13 organizations total in sectors such as defense, health care, energy and transportation are now confirmed to have been breached, cybersecurity firm Palo Alto Networks will warn in a report to be published Thursday.

Palo Alto Networks identified about 600 cases in the US of systems running a type of vulnerable software that the hackers have exploited. That includes installations at 23 universities, 14 state or local governments and 10 health care organizations, the researchers said.

It’s the type of digital spying that the US government has for years tried to expose before it compromises sensitive data related to national security or trade secrets.

The hacking effort shares similarities with the techniques of a group Microsoft has identified as operating in China, Palo Alto Networks said.

The ultimate impact of the computer intrusions is not yet clear because investigations of the breaches are ongoing. But Palo Alto Networks’ Unit 42 researchers believe the hackers could be trying to gain long-term access to computer systems in order to siphon off key data from US companies.

“This adversary has aggressively targeted organizations in the United States and elsewhere in defense, technology and other critical sectors,” Ryan Olson, vice president of Palo Alto Networks’ Unit 42 division, told CNN.

“While we’re still learning more about the impact of these…