Legitimate websites are a growing frontier for malware attacks with over ten million pages affected every year. Security start-up Dasient claimed the threat has risen as more people create their own websites and blogs without proper built-in security protocols.
Anyone opening an infected page could have the malware downloaded to their computer without even realising it.
"There's a real and present danger of the web being seriously compromised," said Dasient co-founder Neil Daswani.
"This emerging threat is becoming very real and is already affecting millions and millions of websites. 30,000 web pages are affected every day according to the likes of Microsoft and the security firm Sophos," said Mr Daswani who was a senior security engineer at Google.