A London council has urged thousands of residents to be “extra vigilant” when receiving calls, emails or text messages after confirming that data had been taken in a cyber-attack.
The Royal Borough of Kensington and Chelsea (RBKC), which has 147,500 residents, said some data had been copied from its systems in an attack this week. The council said it believed the theft related to “historical data” but it was checking whether it contained any personal or financial details of residents, customers or service users.
“With advice from the National Cyber Security Centre (NCSC), we are encouraging all residents, customers, and service users to be extra vigilant when called, emailed or sent text messages,” the council said.
Three London councils have been affected by cyber-attacks this week, with RBKC and Westminster city council saying a number of systems had been affected across both authorities, including phone lines. The borough of Hammersmith and Fulham was also affected and has said it is “working around the clock” to restore its systems.
RBKC said it was working with the NCSC, the National Crime Agency and the Metropolitan police to identify the assailants. The council said it faced at least two weeks of “significant disruption” and was working to bring its systems back online after services were affected.
Public bodies and private businesses across the UK have been hit in recent years by ransomware attacks, where criminal gangs typically based in the former Soviet Union lock up a target’s IT systems with malware and extract data at the same time. The gang members then demand a payment in cryptocurrency for the systems to be decrypted and the data returned.
None of the councils have indicated whether ransomware was involved. Westminster city council and the borough of Hammersmith and Fulham have not confirmed whether data was stolen in their attacks. In 2020 a ransomware attack on Hackney council accessed and encrypted 440,000 files, resulting in a reprimand from the UK’s data watchdog.
The councillor Elizabeth Campbell, the Conservative leader of the Royal Borough of Kensington and Chelsea, said warning residents their data might have been taken was “the right thing to do”.
“All I know is – as a resident myself – I would want to know this information as soon as possible and then be able to make my own choices, follow advice and protect myself if I think necessary.”