SecureMac has released a free utility called DNSChanger Removal Tool to remove the DNSChanger Trojan Horse, also known as OSX.RSPlug.A and OSX/Puper, which has been found on numerous pornographic websites disguising itself as a video codec. Once downloaded and installed, DNSChanger changes the DNS settings on the computer, redirecting websites entered by the user to malicious sites. If personal information is entered on these malicious websites, it can lead to identity theft.
If the DNSChanger trojan horse is detected, DNSChanger Removal Tool will give you the option to remove it. If the DNSChanger trojan horse is detected and removed, you will need to restart your computer to clear out the bad DNS entries added by the DNSChanger Trojan Horse.
More info and download link (174KB) here.