Town hall chiefs have issued a warning after a major data breach.
Lewisham council officers are contacting around 6,000 people who they believe may have had their financial data hacked.
They first became aware of the attack on April 24 when they were subject to a ransomware attack.
A ransomware attack is when the data on an organisation’s computer is locked by encryption.
The targeted organisation is asked to pay a ransom in a virtual currency, such as Bitcoin, in order to release the data.
The council had been using a portal outside of the main IT network to conduct data analysis for a homelessness project.
This portal was then infiltrated by an outside agent. They have reported this to the police who are now investigating.
It is possible that personal data from council tax, housing benefits, adult social care, education and planning could have been stolen.
Ian Thomas, Chief Executive of Lewisham Council, said: “Residents using our services are our highest priority. We sincerely regret this matter and are fully committed to doing everything we can to support those who may be affected.”
The council are not aware of inappropriate use of the data but they are warning people as a precaution.
A spokeswoman said: “We are taking this matter very seriously and have reported it as a crime. We are working with our partners and the appropriate regulators and authorities, and have already implemented a tightening of our security controls. The investigation into the matter continues.”
If you are a resident, you can contact 0800 953 3045 if you have any questions or would like advice.