has my iMac network just been hacked ?

[GilesM]

All, please can you advise. I have wired ethernet LAN with two Imac's connected, mine and my wife's.
This afternoon I happened to look in the finder window and I saw a computer other than mine and my wife's on the network.
It was identified as "mac0022412de870" and when I hit 'get info' it was reported to be a 'pc server'.
I shut down my network and rebooted and the device is no longer connected.
Have I just been hacked ?
This is a hard wired network, on both imac's Airport and bluetooth are both disabled.
Firewall is set to 'allow essential services only' on both iMacs.
Stealth mode is active on both iMacs.

Any ideas ? Please...

 

[NEiMac]

Is your wireless internet protected with a password? I think someone was using your internet connection is what that was, Im sure someone who knows more about this sort of thing can tell you for sure.

 

[GilesM]

well, that is the strange thing, this is a wired network, I have no wireless connections in the house, I do not trust them you see.
Could it be that my Imac was picking up on someone else's wireless network ? I was sure all wifi stuff was turned off in my iMac.
The wireless connection is called "airport" right ? well this has never been turned on it's always off.

 

[Gray-Wolf]

Short of VNC or some sort coming in through the IP addy, not sure what could do this.

 

[Mr Kram]

does the router have wireless capability? if so, is this turned off?

 

[zephead]

Do you have Windows installed on either computer, either through Boot Camp or Parallels/VMWare? Sometimes your Windows file server will show up, even though Windows isn't running. I've seen this happen a few times with mine.

 

[GilesM]

The router has no wireless capability.
There is a windows XP laptop on the network but it has been turned off for 48 hours (it's the one I am forced to use by my employer).

It seems clear that this description was the mac address of a device.
Is there any way to trace it ?
I wonder of it is the mac address of the router ? Is that possible ?
I will check both imacs again and ensure that the Airport is off, but I am really sure it is.

Curious.

Additional edit.

Just prior to noticing this device on my network, i had an unsolicited chat attempt from a skype user called "Sexy girl 18" or some such rubbish. i rejected the chat attempt and blocked the user name.
Since then I have ensured that Skype only accepts voice or chat traffic from those already in my contact list.
Could it be that this individual used skype to attach a windows machine to my network ?

I have also turned file sharing and screen sharing off. I guess I will have to turn those on again manually when my dear old mother needs help with her Macbook (I screen share her screen to show her how to do stuff).

I guess all I can do now is keep an eye on it and see if this mysterious device appears again.

Any other advice ? Is there anything else I can do ?