Some 43 per cent of companies hit by distributed denial of service (DDoS) attacks believe they were targeted by a rival firm, according to Kaspersky Lab.
Research carried out by the vendor in conjunction with B2B International shows that businesses saw their competitors as their biggest cyber threat in 2016, greater than cyber criminals who only 38 per cent of firms believed to be their attacker.
The global figure is higher than in western Europe, with only 37 per cent of western European firms suspecting foul play by a rival.
A DDoS attack occurs when a system is flooded by a high volume of traffic, causing it to crash.
"It is clear that businesses feel their IT systems and private data are under siege from all sides," said Kirill Ilganaev, head of Kaspersky DDoS protection at Kaspersky Lab.
"With DDoS attacks becoming so frequent and so crippling, many suspect their competitors are behind them, as they look for ways to put their rivals out of action and steal their customers as a result."
Following competitors and cyber criminals, 21 per cent of businesses believed the attacks were made by disgruntled employees, with 20 per cent suspecting foreign governments and secret service organisations.
For the study, Kaspersky Labs surveyed 4,000 businesses of varying sizes in 2016, from 25 countries.
The research found SMBs to be more suspicious than enterprises, with 48 per cent believing a rival to be their attacker. The figure however dropped to 36 per cent for businesses with over 1,000 employees.
Larger companies, Kaspersky claimed, tended to point the finger more at former employees and foreign governments.
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