Wales’ largest car dealership was held to ransom by hackers who tried to access its computer systems.
Sinclair Motor Holdings was forced to lock down its IT and phone systems when criminals tried using malware to hack into its computers and demand a ransom.
The company, which has 18 retail outlets across South Wales, declined to say how much money was demanded.
Corrupted equipment had to be replaced after the shutdown, which caused “significant disruption” to business.
But customers have been reassured that no customer data was accessed during last week’s attack.
Andy Sinclair, group director, said: “The lock-down of our IT and telephone systems for several days placed a huge challenge on our operations and delivering the service levels that our customers have come to expect from us.
“For those customers who may have experienced difficulties in contacting us, I can only apologise for any disruption, delays or inconvenience caused – all can rest assured that we are now very close to the resumption of normal service across our business.”
Specialist police officers are continuing to investigate the incident.
The company has now employed a team of cyber-security experts to review its security systems.
A spokeswoman for South Wales Police said: “We can confirm a report from the Sinclair Motor Group relating to a cyber attack on its IT Infrastructure, has been received.
“The matter is being investigated by specialist officers from the Digital Forensic and Cyber Crime Unit.”
Acting Detective Chief Inspector Mike Yeo said: “The investigation is well under way and we are working closely with our partners both nationally and internationally to establish the source of the malware infection and those responsible for the attack.
“This incident has caused a significant disruption to the Sinclair Motor Group and I would urge all businesses, regardless of the size, to consider the advice given out by the National Cyber Security Centre, particularly guidance relating to the backing up of data on a regular basis offline and ensuring that passwords are sufficiently complex in order to protect their organisation.
“South Wales Police also works closely with Get Safe Online who provide comprehensive advice on a wide range of subjects.