$ sudo -u root cat /etc/sudoers | grep NOPASSWD | grep -v ^# | wc -lIf it returns a 0, everything is fine... if not... you might be infected, or you modified the sudoers file yourself.
Check if your Mac OS X is ‘infected’
Some of you might have read the posting about the infection issues on Mac OS X
I just looked into it and guess it's easy to detect if you're 'infected':
