The malware claims to undertake an antivirus scan and displays a fake message stating that the visitor's computer has been infected.
The visitor is then urged to purchase a bogus security product to clean up the 'infection'.
Sophos warned that it would be "trivial" for the hackers who have compromised the web pages to alter the payload so that it became more malicious.
They could install code designed to harvest confidential information from users, or turn innocent victims' PCs into botnet zombies.
"There are millions of video game lovers around the world, many of whom will visit Sony's PlayStation website regularly to find out more about the latest console games," said Graham Cluley, senior technology consultant at Sophos.
"Most would never expect that surfing a website like this could potentially infect them with malware.
"It is essential that all websites, especially high profile ones like this, have been properly hardened to prevent hackers from injecting malicious code into legitimate web pages."
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iTnews Executive Retreat - Security Leaders Edition
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