San Francisco Municipal Railway riders got an unexpected surprise this weekend after the system’s computer systems were apparently hacked. According to the San Francisco Examiner, the MUNI system had been attacked on Friday afternoon.

MUNI riders were greeted with printed “Out of Service” and “Metro Free” signs on ticket machines on late on Friday and Saturday. MUNI first became aware of the intrusion on Friday, according to the Examiner.

Computer screens at MUNI stations displayed a message: “You Hacked, ALL Data Encrypted. Contact For Key(cryptom27@yandex.com)ID:681 ,Enter.” MUNI Spokesman Paul Rose spoke to the Examiner and noted that his agency was “working to resolve the situation,” but refused to provide additional details.

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