I was at work using my phone. We have an open WIFI, but I did not use it to go online. I was wondering, can my information be viewed or was I transmitting data even though my phone said I was not connected to their WIFI?
If you are connected to a mobile network instead of your companies wifi they shouldn't be able to view traffic coming from your phone. However, if the phone is a work phone (provided by them) then the statement above may not apply; they could have installed applications designed to monitor employees.
There is also another complication regarding Wifi too for example if your phone automatically connects to x SSID. Your phone must broadcast a probe signal for known SSIDs that you have connected which can be logged using airmon (part of Aircrack suite). If I create a fake BBSID using tool such as airbase-ng (Part of the Aircrack suite) which your phone has been probing for you will automatically connect to me thus allowing me to to deal with your way your phone deals with network. Hell, you could even do some pentesting against phone now that your networked to the attacker.
So, you need to ensure Wifi is not probing for known SSIDs or completely disable your Wifi.
As for 3G too link below: sniffing/recording GSM 3G signals
Theoretically it's possible to monitor 2/3G signals with the correct equipment. I've never seen it happen in person.
If they was doing some of methods above this would have to be in your work contract that you signed otherwise it would be beaching your privacy. Anyways, who's going to spend that amount of time and effort monitoring all that? Unless your working as GCHQ. :p
If your device is not connected via Wifi, you don't transfer information via Wifi. If it's a company phone, they could monitor what you do, even for apps that never connect to the internet.
If you connect to your mobile provider (3G etc), then it depends. At our office we have bad reception. We bought a device that provides a 3G connection for one specific mobile provider. This device is connected to our network. I have no idea if this traffic is encrypted and safe.
I just asked another question about this:
If you are using your personal cell phone with no Enterprise MDM app installed and no connection to your work WIFI-then short answer: "No"
If it is a work phone and it has an Enterprise MDM app installed, then it is possible they log that data whether you are on company WIFI or using cell. It just depends on how they set things up.
It depends on what service they use. If they use company router to monitor and restrict the mobile phone activity, they have few chance to know what you are doing.
With these apps installed, the data transmit doesn't require Wifi. They may use cellular or 3G network.