Mydoom variants discovered in the wild - MyDoom.C aka SyncZ

Yet another Mydoom variant has been found in the wild, according to an alert sent out by iDefense Inc. this morning.
Known as Mydoom.C or SyncZ, the malicious code appears to be scanning the Internet for systems already infected by the original Mydoom. When finding a vulnerable machine, it uploads itself via TCP Port 3127, and creates a copy of itself in the Windows System directory as "intrenat.exe" as well as several other files in various Windows directories.

This virus, like the Mydoom.B version before it, attempts to find so-called zombie computers to launch a denial-of-service (DoS) attack on Microsoft's Web site. However, it does not appear to seek to e-mail itself to other systems.

This latest version is unlikely to affect U.S. corporate networks that successfully defended against the initial MyDoom virus, said Ken Dunham, director of malicious code at iDefense, a security consulting company in Reston, Va. However, with many home, small-business and overseas systems potentially still infected, the worm has the potential of launching a successful DoS attack against the Microsoft.com Web site -- which would affect businesses that need to access that site for patches, updates and other information.