The survey showed 87% of small firms - up 10% - experienced a security breach last year and 93% of large organisations had also been targeted.
The number of cyber attacks hitting businesses has soared in the past year, Government-commissioned research has revealed.
The Information Security Breaches Survey, commissioned by the Department for Business, Innovation and Skills (BIS), found some of the incidents caused more than £1 million of damage.
Affected companies experienced around 50% more attacks on average than a year ago, with the median number of breaches suffered by large organisations up from 71 to 113 and the figure for small firms rising from 11 to 17.
The Government has increased support for small firms to help them protect against electronic attacks.
The Technology Strategy Board has extended a scheme to allow small and medium enterprises (SMEs) to bid for up to £5,000 from a £500,000 pot to improve their cyber security by bringing in outside expertise.
BIS is also publishing guidance to help small firms make cyber security part of their normal risk management procedures.
Universities and Science Minister David Willetts said: "Keeping electronic information safe and secure is vital to a business's bottom line.
"Companies are more at risk than ever of having their cyber security compromised, in particular small businesses, and no sector is immune from attack. But there are simple steps that can be taken to prevent the majority of incidents.
"The package of support we are announcing today will help small businesses protect valuable assets like financial information, websites, equipment, software and intellectual property, driving growth and keeping UK businesses ahead in the global race."