A study that has been conducted by the AVAST Virus Lab has identified un-patched and pirated versions of Windows XP as the perfect target for rootkit infection. The study found that rootkits infecting via the MBR were responsible for over 62% all rootkit infections. Driver infection made up only 27% of infection. The clear leader in rootkit infection is the Alureon(TDL4/TDL3) family, responsible for 74% of infections.
TDL4 is a rootkit that is able to bypass security mechanism in the digital signature at x64 Windows version. Author used a special technique to infect MBR so it allows launching the malicious code before the operating system itself.
Compromises involving rootkits usually run undetected and make an infected PC available to the controllers of botnets for cybercrime such as sending spam – or spreading malware to other machines.
Now it’s very important to note that using a pirated version will let you open to new malwares as you will have no OS security update. So besides using a licensed OS version make sure to keep your antivirus software installed and updated and for advanced security tips make sure to apply the Ten steps To Protect MS Based System.