17

Currently I have no way to know if my machine is being remotely viewed by our tech support, and would prefer to know, given the massive privacy breach that would entail should this be happening. I am running Mac OS X Snow Leopard.

Running

ps -A | grep Remote

I know this service is running:

/System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/MacOS/ARDAgent

My knowledge of administration of Macs on a network is limited, so I don't know what tools allow this.

3
  • 2
    Note that the below two answers only cover the built-in screen sharing tools in OSX. There are also third party tools that may or may not display any icons at all when somebody is viewing your screen. Vine Server, for instance will not show any indication that it is running or that somebody is connected. As a professional IT admin, my best answer is that, if this is a work owned machine, you probably shouldn't be doing anything with it that requires privacy, as you should expect none.
    – RESPAWN
    Aug 1, 2012 at 14:45
  • macOS Sierra (aka 10.12) introduced a new log tool that can interpret incoming screen sharing connections (run as sudo or root): log stream --predicate 'eventMessage contains "Authentication"'
    – da4
    Mar 15, 2017 at 18:14
  • Note this is not necessarily a privacy breach - your contract might allow your employer to do this - so read your contract.
    – mmmmmm
    Sep 20, 2021 at 9:09

8 Answers 8

20

If your computer is being remotely accessed, it will show a little viewer icon in the menu bar. (Note, I've been using screen sharing since OS X Leopard, and I've never seen the icon noted by de_an777 in his answer.

Go into System Preferences > Shared. Make sure that Screen Sharing and Remote Management (for Apple's Remote Desktop) are both unchecked.

Also, check under Security & Privacy > Firewall and turn the Firewall on. Note the warning. "The firewall will block all sharing services, such as file sharing, screen sharing, iChat Bonjour, and iTunes music sharing. If you want to allow sharing services, click Advanced and deselect the “Block all incoming connections” checkbox."

This will block any incoming screen sharing connection (as well as other services).

To check to make sure that you can't connect to your computer via screen sharing, you can use nmap, a free command line tool for "network discovery and security auditing."

To use it, just type nmap [YOUR IP ADDRESS]

You'll see that nmap reports that the vnc (screen sharing) port is open. After turning off screen sharing and turning on the firewall:

(Note that I've explicitly allowed ssh, printer, and afp sharing in the Firewall.)

I hope this helps you!

2
  • The screen sharing icon that appears in my answer is in mountain lion. They have updated the icon, that's why I said that you will see this icon, or something similar to a screen with binoculars depending on your system.
    – de_an777
    Aug 1, 2012 at 12:41
  • Ah. I see. I didn't notice that you said that.
    – daviesgeek
    Aug 1, 2012 at 16:49
5

I came here because I noticed my mouse pointer moving around in a distinctly human way without me moving my mouse. I realize this isn't strictly an answer to your question but it may help someone:

It turned out that my office Mac had previously been owned by other people in my office, and was still paired with their Bluetooth mice. Their mice sometimes connected to my machine and then they were waving their mouse around trying to figure out why it wasn't controlling their own computers.

You can unpair mice by going to the mouse settings and clicking the "set up Bluetooth mouse" button, then clicking the "X" next to devices you don't recognize as your own.

5

Interesting, I just had the same annoyance. IT logged in, moved my mouse, viewed a few things and I thought, "hang on, there's no indicator at all this is happening..."

The other answers seem correct, however I had an additional thought - this checkbox.

enter image description here

3rd one down "Show when being observed". This was unchecked, presumably from when my machine was originally set up.

My machine is <1 month old, a replacement/upgrade, I have admin rights but still need IT for a range of things. I was/am spewing that this was the default setting.

3
  • I don't see an answer in this question, you might could improve your reply with a more detailed answer instead of a "I've had the same", as that is no answer unfortunately.
    – Rob
    Feb 28, 2014 at 8:37
  • 3
    @Robuust No idea what you're talking about. I've explicitly pointed out a checkbox that directly relates to the question being asked, a checkbox no one else has brought up. The 'I've had the same' is providing a bit of context, no harm in that.
    – nzcoops
    Mar 20, 2014 at 6:03
  • You also have to ensure the "show icon on toolbar" selection in the "computer settings.." box. I added an answer with more screenshots. If you don't have the icon showing then nothing will tell you you are being observed even if you have "Show when being observed" checked.
    – pathfinder
    Sep 20, 2021 at 16:40
4

Usually, if your mac is being monitored, if will show this image in the top right hand corner near your time:

enter image description here

When that symbol appears, or a symbol that looks very similar to it, like a screen with binoculars in it, it depends on your system , you will be able to tell if you are being monitored. You can also disconnect the viewer like so:

enter image description here

Also, if you have access to your settings with an administrative account you can go to:

System Preferences > Sharing

enter image description here

Make sure Remote Management is Off and that Screen Sharing is Off. If both of these are off then you can not Remote Control/View the Mac over the network through VNC.

I hope that this information helps you keep your privacy safe.

4

I guess the problem with the other two answers is that you may not notice the icon in the top right corner of your screen.

What you need is an app that alerts you about any new connections. Little Snitch does this. Whenever a new connection is trying to be made with your computer, little snitch pops up and asks you if you want to allow it or deny once or forever. Really simple and useful app. Can be a bit of a pain at first until you get rules in place for all your applications that access the internet but you'll find after a day or two it won't bother you very often at all.

3

If you have access to the command line, then 'netstat -n' will show the active network connections at the top of the list. The local port should be 5900, so you would be looking under "Local Addresses" for a connection with your machine's IP address and a ".5900". The "Foreign Address" will be the IP address of the machine doing the monitoring.

Note that the company can lock you out of the command line as well, if this is a centrally managed machine, and/or log your use of applications on the machine.

Not that you asked, but I don't know if it is reasonable to have any expectations of privacy on a company owned machine. :-)

1

Not sure this will satisfy the OP's desire to see when it's happening in real time but I usually use the following to see ScreenSharing events: syslog -w -k Sender screensharingd

1

In 2021 on Big Sur:

  1. Open System Preferences and go to sharing.

  2. Click on Remote Management

enter image description here

  1. Click on "Computer Settings"

  2. Be sure to check the box that puts an icon on your toolbar. If you do not, then the step 5 below will not work and you will have no idea someone is observing or remotely managing. -- Binocular Icon when nobody is connected -- Two boxes overlapping when someone is watching or has control. If you click the icon it will tell you if they are only observing or if they have total control.

enter image description here

  1. The above setting in number 4 will only properly work if you have also clicked through the "Options..." button and checked "show when being observed" box. Additionally, you have a more granular ability to choose what can be observed/managed. If you do not do both steps 4 and 5, neither will function as you expect and you will not know you are being observed.

enter image description here

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