Naughty hackers have found a way of bypassing The Warden anti-cheating program in World of Warcraft - by making use of Sony content protection software.
The "rootkit" software is included on many of Sony BMG's music CDs, and can be used to hide files simply by naming them with the prefix "$sys$".
A new patch to make the files unhidden was released last week by Sony and technology developer First 4 Internet, much to the dismay of groups campaigning for the protection of net privacy, but installation is optional.
This isn't the first time The Warden has come under scrutiny by net activists, who have previously claimed it is a form of spyware after software engineer Greg Hoglund found that it scans PCs to establish which other programs are running.
"I watched The Warden sniff down the e-mail addresses of people I was communicating with on MSN, the URL of several websites that I had open at the time, and the names of all my running programs," Hoglund said.
WOW developer Blizzard responded by arguing that The Warden did not obtain personally identifiable information, and that the data was used for no other purpose than to find evidence of cheating or hacking.
Blizzard has yet to comment on the use of the Sony rootkit by hackers.