SAN FRANCISCO (CBS SF) — ‘You Hacked, ALL Data Encrypted.’

That was the message on San Francisco Muni station computer screens across the city, giving passengers free rides all day on Saturday.

Inside sources say the system has been hacked for days.

SFMTA has officially confirmed the hack, but says it has not affected any service.

A spokesperson with the transit agency tells KPIX 5 it is an ongoing investigation.

“There’s no impact to the transit service, but we have opened the fare gates as a precaution to minimize customer impact,” said Muni spokesperson Paul Rose. “Because this is an ongoing investigation it would not be appropriate to provide additional details at this point.”

“I think it is terrifying,” said one rider. “I really do I think if they can start doing this you know here, we’re not safe anywhere.”

“I was like, is this part of Black Friday deal, or something?” added another.

Meanwhile, riders will continue to find the metro gates open, and the system is not reading their payment cards. The fare gates were still wide open Saturday at 6 p.m. at the Embarcadero Station.

Ticket kiosks were also out of service.

SFMTA says they are working to resolve the issue.

The hack affects employees, as well. According to sources, SFMTA workers are not sure if they will get paid this week.

Cyber attackers also hit Muni’s email systems.

The transit agency has no idea who is behind it, or what the hackers are demanding in return.