Sophos has released a free tool to help PC users root out rootkits.Called Sophos Anti-Rootkit, the software will detect and remove both known and unknown rootkits, and it will also warn system administrators if removing the software might harm operating system integrity.Rootkits are a collection of tools used by hackers to gain administrative privileges on compromised machines. They are typically used to help hide other forms of malware\u2014keyloggers or Trojan horse programs, for example\u2014from antivirus software.Late last year, Sony BMG Music Entertainment helped make rootkit a household word, after the company was forced to recall millions of CDs that used these cloaking techniques to hide its copy-protection software. Sony\u2019s rootkit, which was installed when customers tried to play CDs, actually compromised PC security. Hackers eventually released malicious software that used Sony\u2019s software to hide itself on a PC.Sophos Anti-Rootkit works with the Windows NT, 2000, XP and Windows Server 2003 operating systems. The software features a graphical interface to help guide users through the process of detecting and removing the malicious software.Since the Sony fiasco, the security industry has paid more attention to the rootkit problem, and there are now a number of free utilities designed to identify this type of software. Other tools include RootkitRevealer, GMER and IceSword.Sophos Anti-Rootkit can be downloaded here.-Robert McMillan, IDG News Service (San Francisco Bureau)Check out our CIO News Alerts and Tech Informer pages for more updated news coverage.