updated 06:45 pm EST, Thu January 3, 2008
Trojan removal tool
SecureMac has announced a free Trojan Detection Tool dubbed DNSChanger Removal Tool. DNSChanger Removal Tool detects and removes latest spyware targeting Mac OS X: DNSChanger Trojan (also known as OSX.RSPlug.A Trojan Horse). This trojan attacks users attempting to play a fake video file. Affected systems are used to hijack some Web requests that lead users to other phishing sites, or simply display ads for other pornographic websites to generate ad revenue. Phishing attacks may lead users to believe they are surfing to eBay, Paypal, or various banks when in fact they are accessing specially-crafted mockups designed to retrieve usernames and passwords for those sites. Upon attempting to play the video, the victim receives the following message: "Quicktime Player is unable to play movie file. Please click here to download new version of codec."
The user's DNS records are modified, redirecting incoming internet traffic through the attacker's servers, where it can be hijacked and injected with malicious websites and pornographic advertisements. The trojan also installs a watchdog process that ensures the victim's DNS records stay modified on a minute-by-minute basis.
The trojan is rated as a critical risk by Intego, and is known to affect Mac OS X 10.4 Tiger as well as Mac OS X 10.5 Leopard. Intego is testing prior versions of Mac OS X, but believes them to be vulnerable as well.
SecureMac's DNSChanger Removal Tool allows users to check to see if the trojan has been installed on their computer; if it has, the software helps to identify and remove the offending file. After a system reboot, the users' DNS records will be repaired.