Global accountancy firm Deloitte admits cyber attack

Global accounting firm Deloitte has admitted it was the victim of a cyberattack which may have revealed sensitive emails belonging to some of its clients.

The company, which is one of the world's 'big four' accountancy firms, released a statement in response to media reports that its data had been compromised.

While asserting that "only very few clients were impacted" by the attack, Deloitte did reveal the attackers had accessed data held on its email platform.

It said that it had since completed a full review of the attack, including "mobilising a team of cyber-security and confidentiality experts inside and outside of Deloitte" and had informed all affected clients.

The Guardian newspaper reported the attack took place in October or November last year, but went undetected by the firm until March.

Deloitte provides auditing services, tax consultancy and financial risk advice to some of the world's biggest companies.

The attack is particularly embarrassing for the firm as one of the areas it advises on is how to safeguard businesses against cyber assaults.

"No disruption has occurred to client businesses, to Deloitte's ability to continue to serve clients, or to consumers," a spokesperson for the company said.

"Deloitte remains deeply committed to ensuring that its cyber-security defences are best in class, to investing heavily in protecting confidential information and to continually reviewing and enhancing cyber security."

The firm is not the first high-profile company to have been targeted by cybercriminals in recent weeks.

Equifax (NYSE: EFX - news) , which is one of the world's largest credit checking companies, revealed last month that data belonging to 143 million customers may have been compromised in a security breach earlier this year.

It is thought to be one of the largest data breaches in history, with up to 400,000 Britons thought to have had personal information stolen in the hack.