A computer security firm said it had discovered the first virus that <A HREF="http://www.cnn.com/2005/TECH/internet/11/10/sony.hack.reut/index.html">uses Sony BMG's controversial CD copy-protection software</A> to hide on PCs and wreak havoc. Under a subject line containing the words "Photo approval," a hacker has mass-mailed the so-called Stinx-E trojan virus, which may tear down a computer's firewall and give hackers access to a PC, to British email addresses. The malware hides by using Sony BMG software that is also hidden--the software would have been installed on a computer when consumers played Sony's copy-protected music CDs.