More than a third of public sector decision makers say their organisation was hit by at least one denial of service (DDoS) attack over the past year, according to new research.

The figures, published by supplier BT show that 36% of public sector respondents to a survey said they had been affected, with 75% of these saying they were hit more than once.

DDoS attacks are seen as a key concern by more than a third of UK organisations in both the public and private sector, the results showed, compared to 58% across the whole world.

Mark Hughes, president of BT security, said: “DDoS attacks have evolved significantly in the last few years and are now a legitimate business concern.

“They can have a damaging effect on revenues and send an organisation into full crisis mode. Reputations, revenue and customer confidence are on the line following a DDoS attack, not to mention the upfront time and cost that it takes an organisation to recover following an attack.

“Organisations need a higher level security solution to protect not only the network infrastructure but the devices that initially provide protection.”

The research also found that only a half of public sector IT decision makers said their organisation has a response plan in place for such attacks, compared to a figure of 60% across all sectors.

In addition, only 17% said that their public sector organisation allocates sufficient resources to defending against DDoS incidents.

More than half of those surveyed in the UK said that such hackers are becoming more effective at breaching security defences.

On average, the volume of customer complaints received jumped 40 per cent following a DDoS attack.

The report said: “This may be a result of the time taken for normal services to resume following an attack – 58% of organisations say their systems were taken down for more than six hours – almost a full working day.”