Is my Mac under a 'man in the middle attack'?

The Network Utility is in the /System/Library/CoreServices/ folder. A Windows virus cannot "leak" through to the Mac.

I don't know anything more related to your problem.

Helpful Links Regarding Malware Protection

An excellent link to read is Tom Reed's Mac Malware Guide.

Also, visit The XLab FAQs and read Detecting and avoiding malware and spyware.

See these Apple articles:

Mac OS X Snow Leopard and malware detection

OS X Lion- Protect your Mac from malware

OS X Mountain Lion- Protect your Mac from malware

About file quarantine in OS X

If you require anti-virus protection Thomas Reed recommends using Dr.Web Light from the App Store. It's free, and since it's from the App Store, it won't destabilize the system. If you prefer one of the better known commercial products, then Thomas recommends using Sophos.(Thank you to Thomas Reed for these recommendations.) If you already use Sophos, then be aware of this if you are using Mavericks: OS X Mavericks- Sophos Anti-Virus on-access scanner versions 8.0 - 9.1 may cause unexpected restarts

From user Joe Bailey comes this equally useful advice:

The facts are:

1. There is no anti-malware software that can detect 100% of the malware out there.

2. There is no anti-malware that can detect anything targeting the Mac because there

is no Mac malware in the wild, and therefore, no "signatures" to detect.

3. The very best way to prevent the most attacks is for you as the user to be aware that

the most successful malware attacks rely on very sophisticated social engineering

techniques preying on human avarice, ****, and fear.

4. Internet popups saying the FBI, NSA, Microsoft, your ISP has detected malware on

your computer is intended to entice you to install their malware thinking it is a

protection against malware.

5. Some of the anti-malware products on the market are worse than the malware

from which they purport to protect you.

6. Be cautious where you go on the internet.

7. Only download anything from sites you know are safe.

8. Avoid links you receive in email, always be suspicious even if you get something

you think is from a friend, but you were not expecting.

9. If there is any question in your mind, then assume it is malware.

I was told when buying the mac that they don't get virus'.

You were told correctly. There are no known viruses for OSX.

More info overload:

Viruses:

Are programs that earn their name by their ability to replicate themselves locally & often across a network. Many attach themselves to to other programs. When you launch one of these programs, the virus code launches as well & the virus goes about its nefarious business.

Viruses are exceedingly rare on the Mac. There are no known viruses for OSX.

Trojans:

Promises one thing but delivers another. You can download a program but when you run the program, the contents of your computer are instead beamed to an underground data center in Kamchatka. If you obtain software from reliable sites, you are unlikely to get a Trojan horse.

Adware:

Has an embedded advertising component - one that displays or downloads ads when you run the software. Some adware is legitimate, part of the price of using a free program such as the Iconfactory's Twitterrific or Eudora for example.

Spyware:

Grabs data from your computer & ofen uses it for the purposes of evil, sending personal info to a baddie or when you're using your web browser, redirecting you to site you don't want to visit.

Mac users have nothing to worry about regarding Spyware & Adware because in order for the worse forms to work, the OS must allow unrestricted access to its more sensitive parts. The Mac OS doesn't.

My guess is that your wireless router has been hacked, and is probably causing you to use a malicious DNS server that is fooling sites into thinking you're located in another country. Reset your wireless router to factory settings. Be sure to disable remote administration, and update the firmware. Use a strong password on the network, and make sure it's protected with WPA2 encryption. Set the administration password to be different from the password required to join the network.

If you don't know how to do any of that, contact the manufacturer of your router.