I have a friend who's having an issue with his wireless and someone apparently managing to gain access. The router is enabled with WPA2 and MAC address filtering. The following is what he advised me via MSN:

when you open network in my computer a phone called occam appears intermittently, it's an Nexus 4 and it has a MAC address that does not match anything in the house, including the two smartphones with connections, (which do not show up in there anyway) checked the router to see if someone was trying to sponge off the wifi (again), but it is never shown up as a connected device only signs of potential weirdness is in data downloaded on the router's status... it seems higher than it should be

Anyone any idea what the hell is going on?

Does the computer he uses have bluetooth enabled?

Does it have the software installed? Disable any drivers/software for the phone and if poss, disable bluetooth. I'd probably change the router password, change and hide the SSID and go from there. If you can disable the wireless aspect of it and run just cabled, it'll give a better idea of whether it's outside or inside (eg computer itself).

No Bluetooth on the computer.

By way of additional information, whoever owns this device had managed to hack the router when it just had a WPA2 key on it and change all the settings. As such, I suspect hiding the SSID will be pointless. This is also why the MAC address filtering was added.

If he's spoofing the MAC address then I guess it won't show as an additional wireless client on the router.

Hiding the SSID actually makes it slightly easier to hack WPA because it increases the amount of chatter when no data is being transferred.

However, it can take a long time to crack WPA2 so if he changes the password regularly, the guy might give up. Also, if he switches the wireless off when it's not in use then that will also hinder any attacker.

PITA I know, but if someone is going to that length to break into the network then you don't know what else they might be able to find out. It's a lot of effort just for free WiFi.

what router ?
is it a BT home hub as they may have enabled the router to be a hotspot
you will have to contact BT to get it disabled

does the router have a guest network wifi setup
if so disable it ...

Thanks for the responses... and thanks jonlumb for posting on my behalf...

Now i've got my login sorted out... now to answer you questions...

Neither of the PCs have bluetooth

passkey is checked semi-regularly, SSID generally not... though it has been changed a few times recently...

SSID is not hidden

the devices, of which there have been 3, only appear when wifi is enabled on the router. they don;t show as a connected device on the router but the do show up in the 'Network' section of My Computer [which is also odd as the 2 smartphones in the house don't]

router does have a guest wifi option, which is always turned off,

and finally router is a Netgear VMDG485 aka the Virgin Media 'SuperHub'