Lincolnshire County Council's website has been down for five days, following a ransomware attack demanding 1 million.
The malware infected the council's online systems as well as its public-facing website and encrypted all the files, saying it would not unscramble them unless the council paid the money.
A tweet posted on the council's official feed yesterday read: "Following a malware attack, the majority of our systems will be back online by tomorrow morning. No data has been stolen. Thank you"
Although the sites were taken offline, the council said only a few files were encrypted by the malware and added the website should be up and running again early this week. Everything appeared to be functioning normally at the time of writing.
The authority confirmed it was a zero-day attack, adding that it was unfortunate it was the first organisation to have been targeted with this particular malware and that security experts were not previously aware of this particular type of ransomware.
"People can only use pens and paper, we've gone back a few years," the council's CIO Judith Hetherington-Smith told the BBC.
"[The attack] happened very quickly. Once we identified it we shut the network down, but some damage is always done before you get to that point - and some files have been locked by the software.
She added that many of the files hit can be restored from the back-up, so all was not lost in the attack.
Lincolnshire Police is investigating into the attack to try and determine who would make such demands.
