Sony's software, installed when playing one of the record label's recent copy-protected CDs in a computer, hides itself on hard drives using a powerful programming tool called a "rootkit." But the tool leaves the door open behind it, allowing other software--including viruses--to be.
The first version of a Trojan horse spotted early Thursday, which aims to give an attacker complete remote control over an infected computer, didn't work well. But over the course of the day, several others emerged that apparently fixed early flaws.
"This is no longer a theoretical vulnerability; it is a real vulnerability," said Sam Curry, vice president of Computer Associates' eTrust Security Management division. "This is no longer about digital rights management or content protection, this is about people having their PCs taken over."
Sony's use of the rootkit software has sparked a firestorm of criticism online and off over the company's techniques, highlighting concerns that remain over record labels' increasingly ambitious attempts to control the ways consumers can use purchased music.Last week, plaintiffs' attorney Alan Himmelfarb filed a class action suit against Sony BMG in Los Angeles federal court, asserting that the company had violated state and federal statues on unauthorized computer tampering. The company's actions also constituted fraud, trespass and false advertising, the suit contends.
Other attorneys say they are considering other suits. Several Italian consumer groups also have said they are looking into the prospect of taking legal action against Sony, although the relevant discs were distributed by the record label's U.S. division and not intended for overseas sale.
Sony's use of the rootkit stems from record companies' growing concerns that unrestricted music copying is undermining their sales, and they have been looking for a technological way to limit the number of copies that people can make of each CD they buy.
Sony BMG has experimented with several different ways to do this. The current controversy focuses on just one of those tools, created by a British company called First 4 Internet.
The First 4 Internet software, including recent releases from My Morning Jacket and Southern rockers Van Zant. When the albums are put in a computer's CD drive, they ask a listener to click through a consent form, and then install the rootkit copy-protection software on the hard drive.
A rootkit is a tool that takes a high level of control over a computer, potentially even preventing the original computer user from performing certain tasks. In this case, the First 4 Internet hides itself from view in the computer's guts.
One Trojan horse discovered by security companies Thursday is a variant of a pre-existing software distributed by spam e-mail, among other techniques.
One version of the e-mail claims to be from a business publication and says it is using a photograph of the recipient for a soon-to-be published article, according to security company BitDefender. Clicking on the alleged photograph installs the malicious software, which then connects automatically to the Internet Relay Chat chat network, opening up a channel to control the infected computer.
In a new version of the program, the software hides itself using Sony's rootkit tool and then tries to connect to a server on the chat network. The first version of the Trojan was unable to function after hiding itself, security company F-Secure said. However, several other variants have been found that are able to successfully take over control of a computer after hiding under the Sony software.
All virus companies are rating the danger as fairly low so far, since the Trojans seem to be spreading slowly.
Most antivirus companies are releasing versions of their software that identify or remove the Sony software. A patch on the Sony Web site will uncloak the copy protection tools, but computer users must contact Sony's customer service for instructions on removing it altogether.
Neither Himmelfarb nor a Sony BMG spokesman could immediately be reached for comment. A Sony BMG representative contacted last week noted that the software could be easily uninstalled by contacting the company's customer support service for instructions.