A ransomware attack that began on November 25 forced the San Francisco Municipal Transport Authority (SFMTA, or ‘Muni’) to progressively close ticketing machines and open the gates to its railway system.

Through Saturday and into Sunday, passengers were able to ride for free, some thinking it was a Black Friday holiday promotion. The station computers, however, showed the message “You Hacked, ALL Data Encrypted. Contact For Key(cryptom27@yandex.com)ID:681 ,Enter.”

SFMTA has so far given little official information, but did say the attack disrupted some internal computer systems, including email.

All Your Computer’s/Server’s in MUNI-RAILWAY Domain Encrypted By AES 2048Bit!” and demanded 100 bitcoins (about $73,000) for the decryption key.

The disruption to travelers was eliminated when the SFMTA allowed passengers to ride for free. By removing a driving factor from the equation, the hack loses value and the ransom will likely go unpaid.”