NYC's transit authority says it was breached by Chinese hacking group

June 3 (UPI) -- Officials with the Metropolitan Transportation Authority of New York City, North America's largest transit system, says it was infiltrated recently by a hacker group suspected to be tied to the Chinese government.

The MTA said Wednesday that the breach occurred in April, affecting three of its 18 systems, though no operations were impacted and no employee or customer information was leaked.

"The MTA's existing multi-layered security systems worked as designed, preventing spread of the attack, and we continue to strengthen these comprehensive systems and remain vigilant as cyberattacks are a growing global threat," MTA Chief Technology Officer Rafail Portnoy said, according to WABC-TV.

The MTA is North America's largest transportation system.

The attack was first reported by The New York Times, which cited a document that said it resulted in little to no damage, although some 3,700 employees and contractors were required to change their passwords for security reasons.

The Times reported the hackers used the vulnerabilities in the Pulse Connect Secure system to infiltrate the MTA.

Around the time of the attack, it was revealed that Chinese state-sponsored hackers had infiltrated U.S. and European government organizations, as well as defense and technology companies through vulnerabilities in the Pulse Secure system that provides remote access to networks.

The Cybersecurity and Infrastructure Security Agency announced it was aware of hackers exploiting vulnerabilities in an effort to compromise "U.S. government agencies, critical infrastructure entities and private sector organizations." It also offered guidance on how to fix issues of concern.

Cybersecurity firm FireEye, which owns the company the MTA hired to deal with its attack, said in April it was tracking the infiltrations and suspected they were conducted "on behalf of the Chinese government."

The revelation comes amid a surge in cyberattacks targeting the private and public sectors in the United States.

Last month, Russian hackers were blamed for attacking the U.S. Colonial Pipeline, and more recently meat company JBS. The former was attributed to hacker group DarkSide and the latter to REvil, which also goes by the name Sodinokibi.

Late last month, Russia-linked hackers blamed for the SolarWinds attack in December targeted some 150 government agencies, think tanks and non-governmental organizations through a spear-phishing campaign in which they sent emails that appeared to come from the U.S. Agency for International Development.

On Wednesday, a ransomware attack disrupted the ticket buying for a ferry service to Martha's Vineyard and Nantucket, Mass.

As these attacks continue, cybersecurity has become a growing issue for President Joe Biden's administration and prompted Biden to sign an executive order strengthening U.S. cybersecurity. Secretary of Homeland Security Alejandro Mayorkas last month offered a proposed budget for the next fiscal year that included an additional $2.1 billion to boost virtual defenses.