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Securing Zoom Meetings

As you may have heard, the dramatic increase in the use of Zoom meetings has had an unwelcome side effect… “Zoom-bombing” or Zoom “crashing”.  Any meeting that has a link on one of our public UC Davis web pages, even if it requires registration, is especially vulnerable to these meeting crashers. 

Below are some of the things that you, as a Zoom host, can do to prevent crashers from being able to join your session.  You’ll also find a section on how to deal with crashers if they do join your meeting. 

In addition to the tips below, you can also read this Zoom article for more information.


For Small / Private Meetings

Following are recommendations for department or other smaller meetings where you know who all of your participants will be.  Some of these settings can then be adjusted when you schedule a specific meeting but others will be unavailable for all meetings unless you adjust them on the Settings page again.

Before the Meeting

Follow these guidelines and open a browser to change the Settings of your zoom.us account to adjust features.

  • Don’t publish unsecured meeting links on public-facing web pages
  • Don’t share your Private Meeting ID (PMI) freely.  Share it only with colleagues; schedule a meeting with a unique ID for external meetings or for meetings you need to share more widely.
  • Turn off Join Before Host so that crashers can’t join before you
  • Use Meeting Passwords
  • Use the Waiting Room so that people can’t join until the host or co-host grants them access
  • Browse the Large Meeting advice below to see other features you can disable if you don’t need them

After Starting the Meeting

Once your meeting has started, you can take additional actions:

  • Lock the Meeting after starting so that no additional attendees can join.  (Click Security > Lock Meeting)
    • You can also Enable the Waiting Room from the Security link, if you hadn’t already turned it on.
  • Dealing with Meeting Crashers

For Large Events / Meetings

When you are coordinating a larger event where you need to share event information more broadly, such as publishing registration information on a web page, you can add security to the registration process and can also restrict actions participants can take during the meeting.  

Before the Meeting

Follow these guidelines and open a browser to change the Settings of your zoom.us account to adjust features.

Prevent Uninvited Participants from Joining
  • Don’t publish unsecured meeting links on public-facing web pages
  • Don’t use your Private Meeting ID (PMI) for large events.
  • Turn off Join Before Host so that crashers can’t join before you
  • Use Meeting Passwords
  • Use Registration with Manual Approval and Meeting Passwords to control who can join.  Also, disable the “Show Social Share buttons” option so that bombers can’t easily share your event information.
Limit Participant Options

Some of these settings can also be adjusted when you schedule a specific meeting but others will be unavailable for all meetings unless you adjust them on the Settings page again.  Click here for Zoom help on changing Settings.

  • Turn off Screen Sharing for Participants*: On your Zoom settings page, change Screen Sharing to Host Only
  • Limit Chat Options*:  You can choose if attendees can chat with no one or with the host only.
    • If you have a Co-Host, they will still be able to see messages when you restrict it to “Host Only”.
  • Turn Off Annotation*: This tool allows attendees to draw on a shared screen. 
  • Turn Off File Transfer: When enabled, this allows attendees to share files via Chat if they have Chat permissions
  • Mute Audio: In Settings, choose the option to Mute Participants Upon Entry
  • Disable Whiteboard: Turn off the option for participants to share the Whiteboard tool
  • Turn Off Virtual Background: This will prevent users from displaying an image as the background on their video

*The features marked with an asterisk can also be quickly turned on and off during the meeting using the Security menu so if you need them, leave them enabled and then turn them on and off as you use them.

After Starting the Meeting

Once your meeting has started, you can take additional actions:

  • Assign a Co-Host (or two) to help you manage the meeting
  • Muting: Disable the option for participants to unmute themselves. 
    • This can be accessed from the Participants window using Mute All or the More menu
  • Enable Waiting Room or Lock the Meeting soon after starting so that no additional attendees can join. 
    • These options are available from the Security icon in your Zoom toolbar.
  • Open the Manage Participants window so you have easy access to controls and can see who’s speaking
  • Dealing with Meeting Crashers

Dealing with Meeting Crashers

Using the Security Toolbar

If someone crashes your meeting, there are new controls in Zoom to help you disable functions quickly.  This new Security toolbar became available on April 8, 2020 – your Zoom application may need to be updated to see it (check with your IT department on process for updating).  For more on the Security toolbar, see this article from Zoom.

What to do if your meeting is crashed

If you’re hosting a large event where there’s a chance of a crasher, make sure you have at least one person set as co-host and plan ahead for who will do what if there’s a crasher so you can act quickly. 

  • Stay calm – you can shut them down! 
  • Mute All and turn off participant ability to unmute
  • Disable all participant options in the Security tool bar (Sharing, Chatting, Annotating, etc.) 
  • Lock the Meeting
  • Find the culprit(s) in video or participant list and Remove from the meeting
    • If it’s a large event and you can’t find them, if you can proceed with tools shuts down, you can go on with your meeting and the bombers will not be able to take further action.

If you’re able to, while you’re taking these actions, let your attendees know functions have been shut down while you deal with the crashers.  The exact order you do these things in will depend on what’s happening and how quickly you need to remove unwanted content.

Accessing Security Toolbar and Participant Controls

Participant Controls

How to Disable Functions and Remove Crashers

Mute All, Remove Unmute Option

  1. Click on Manage Participants in toolbar
  2. Click Mute All
  3. Uncheck the Allow Participants to Unmute option
  4. Click Yes

Disable Participant Options for Sharing Screen, Drawing (Annotate), Chatting

  1. Click on Security icon in your toolbar
  2. Uncheck all options that appear

Note: Your list of options will be shorter if you have fewer functions enabled for your meeting.

Lock the Meeting - Do this so that removed crashers can’t re-join.

  1. Click on Security icon in your toolbar
  2. Click on Lock Meeting

Note: If you need others to still be able to join, you can could choose Enable waiting room instead and then a host or co-host can choose to let people in.

Remove Participants - Choose an option based on how you’re able to identify who the crasher is.

  • Option 1: Security > Remove Participant
    Use this option when you don’t have a lot of participants and you know who the crasher is.
  • Option 2: Video Controls > Remove
    If you see the crasher on video, hover over their image and the More (…) menu will appear.  Click (…) and then choose Remove
  • Option 3: Participant List > More > Remove
    If you see the crasher in your participant list (those who are speaking will be at the top of the list), hover over the name to find the More menu, then click Remove.

Prevent a Crasher from “Hiding” by Changing Names

  1. Click on Security icon in your toolbar
  2. Uncheck Rename Themselves

Remove Drawings on Screen
To clear any existing drawings on-screen, go to your toolbar and click on Annotate > Clear > Clear All Drawings

Turn Off Video
If you see video from the crasher, use the video controls to remove them.  However, if needed, you can also stop their video

  1. Hover over the person’s video box and the More (…) option will appear
  2. Click on the More (…) button
  3. Click Stop Video

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