FLAGSTAFF, AZ (3TV/CBS 5) - For the second day in a row, the Flagstaff Unified School District said it's forced to close all of its schools because of cybersecurity issues.
There will be no classes for students on Friday, Sept. 6. The FACTS, childcare centers and FUSD preschools will remain closed, officials said.
The district said progress was made on Thursday "in securing critical systems," but work still needed to be done so students can return to school on Monday.
The issue was ransomware. That's when hackers lock you out of your system and threaten to delete your information unless you pay them.
The district said it backed up its systems before the attack, so it is not trying to recover the stolen information or pay the ransom.
Hacking expert Reggie Walls said if the computers weren't backed up, it would be an even bigger problem.
"First you try to talk to an expert, 'Can you crack this?'" said Walls. "Nine times out of 10 those experts either say you pay the ransom or you gotta figure out how to come up with data some other ways."
Walls said that's because the code is incredibly tough to crack.
[WATCH: Ransomware can affect anyone]
Although a similar ransomware attack could happen anywhere, Walls said big banks and cities usually have backups and IT experts who are constantly monitoring computers, making attacks there less likely.
The district said it's working on security updates to make sure this does not happen again.
It also said no one's personal information was compromised.
Students weren't in class on Thursday because employees discovered ransomware on its servers the day before.
The district took down the internet services at all the schools around 3 p.m. on Wednesday.
FUSD schools will be closed on Friday, 9/6, due to the continuing work to respond to the cyber security attack. Progress was made today in securing critical systems, but unfortunately, work will need to continue through the weekend so students can return to school on Monday. pic.twitter.com/kTnbsTLklh— Flagstaff Unified School District (@FlagstaffUSD1) September 6, 2019