Half of all the world's critical financial exchanges have suffered cyber attacks in the past year, a report has found.

A joint investigation by the World Federation of Exchanges and‎ the International Organisation of Securities Commissions found that the attacks are increasingly aimed at destabilising markets, rather than making financial gains.

The authors found that people at the very top of the world's economic system are nervous that a concerned online assault could cripple markets.

Top bankers are increasingly aware of the possible threat but have little confidence in their ability to thwart attacks, with one quarter of respondents admitting their "current preventative and disaster recovery measures may not be able to stand up against a large-scale and coordinated attack". Just half of all exchanges believe their local laws are tough enough to deter hackers.

The exchanges want to see more concerted international efforts to ensure that hackers have no chance to bring down critical systems.

“Doubt over the effectiveness of these regimes generally appears to rest on the international nature of cyber crime, which creates a major obstacle in effective enforcement,” said Rohini Tendulkar, author of the report.

However, even tighter laws might not stave off market Armageddon. Hackers have proved that they don't even need to target financial systems to move the markets. In April, stocks tumbled after the Syrian Electronic Army sent a false tweet from news agency AP's eponymous account claiming that the White House had been attacked and President Obama had been injured.

Siobhan MacDermott, chief policy officer at anti-virus and security firm AVG, has previously warned that the world is already in the grip of a cyber war. As well as flogging anti-virus to punters, MacDermott advises officials from the US, EU, NATO and China.

She told El Reg that even top generals are flummoxed when it comes to cyber security, which will not reassure nervous financial exchange bosses worried about hackers causing cataclysmic damage.

"I sat down with a top-ranking general,” said MacDermott, “and I asked what kept him up at night. He told me that when he was in the military, warfare was simple. You stood on either side of a field, marched into the middle and fought.

"It didn't get that different until the internet came along, he said, but now I'm holding underpowered weaponry and I just don't know where the shots are coming from... This totally changes the dynamic of how you protect assets. It's sort of like having a water pistol and going up against someone with a cyber weapon of mass destruction."

The report said that cyber crime costs the world between $38bn and $1tn, although it is impossible to produce entirely accurate figures due to the indirect costs which are often left out of such calculations. ®