The April 2009 Threatscape Report identified more incidents of new and known malware infections than ever before.
Fortinet said that certain countries and areas are being specifically targeted, and that China had seen the worst attacks. The report also identified online gaming sites as the most common vehicles for infection.
"April was a busy month for cyber criminals, who unleashed the most aggressive malware attacks thus far this year," said Derek Manky, project manager for cyber security and threat research at Fortinet.
"We believe that this upward trend will endure, and that online gaming attacks will continue to dominate the estimated US$2bn annual market."
China endured 45 per cent of global malware infections, almost double the figure found in the firm's last research paper.
Separate research by software-as-a-service security firm ScanSafe found that, while the amount of malware is growing, so is its ability to affect end-user systems. The report said that 58 per cent of the malware it had discovered were 'zero day' threats.
ScanSafe identified a 20 per cent rise in the amount of malware since the end of the last quarter, and a threefold increase since the same period in 2007.
"Zero day malware is increasing and, with signature-based scanners not picking up an average of 20 per cent of malware, it is now crucial to use real-time scanning to ensure that your employees, network and, most importantly, your data is not at risk," said Mary Landesman, senior security researcher at ScanSafe.
"With malware increasing in volume and sophistication, and no foreseeable slowdown in sight, it is more important than ever that companies have a comprehensive web security solution in place."