An illustration of Zoom's attendee attention tracking.

Using Zoom? Here are the privacy issues you need to be aware of

Zoom(new window) has seen a flood of new users as the COVID-19 outbreak forces more and more employees to transition to working from home. Zoom’s big selling point is its near-frictionless video calls.

However, new users should be aware of the company’s privacy practices. By looking through its privacy policy and some of its support documents, you quickly discover that Zoom shares the copious amounts of data it collects with third parties and has already had a major security vulnerability. An investigation by The Intercept(new window) has called into doubt Zoom’s claim of end-to-end encryption on its video calls. And online trolls have also taken advantage of default Zoom settings to “Zoombomb,” public conference calls and disrupt them.

We believe it’s important for our community who may be switching to Zoom in their workplace during the coronavirus outbreak to be aware of these issues, and this post looks at each of them in detail. At the end, we’ll offer some suggestions for what you can do to protect yourself while using Zoom.

Zoom privacy regarding your data

Zoom not only tracks your attention, it tracks you.

According to the company’s privacy policy, Zoom collects reams of data on you, including your name, physical address, email address, phone number, job title, employer. Even if you don’t make an account with Zoom, it will collect and keep data on what type of device you are using, and your IP address. It also collects information from your Facebook profile (if you use Facebook to sign in) and any “information you upload, provide, or create while using the service.”

Some of this data you enter yourself when you are signing in (for example, to join a call online, you must give your email), but much of it is collected automatically by the Zoom app.

In its privacy policy(new window), under the entry “Does Zoom sell Personal Data?” the policy says, “Depends what you mean by ‘sell.’” To summarize Zoom’s policy, they say they don’t sell personal data for money to third parties, but it does share personal data with third parties for those companies’ “business purposes.” In its privacy policy, it gives the example that it may pass your personal information to Google.

An article in Vice(new window) pointed out that the Zoom iOS app shared a substantial amount of user data with Facebook, even if the user does not have a Facebook account. However, two days after this story was published, Zoom removed the code(new window) that sent data to Facebook. In a statement to Vice, Zoom explained it was unaware that the Facebook software development kit (SDK) used to implement the “Login with Facebook” feature in its app was collecting unnecessary data. The statement also listed the types of device data the Facebook SDK had collected, including the mobile operating system (OS) type and version, the device time zone, device OS, device model and carrier, screen size, processor cores, and disk space.

Zoom is now facing a class action lawsuit(new window) from a California resident who alleges that Zoom violated the California Consumer Privacy Act by not getting users’ consent before sharing their data with Facebook. Also, the New York Attorney General’s office recently sent a letter to the company(new window), expressing concern that Zoom’s existing security practices fail to secure its users’ data. The Attorney General’s primary concern is that Zoom may not be doing enough to meet the state’s requirements to protect student data. Zoom recently increased the number of participants allowed on its free calls to help teachers and schools reach students at home.

Zoom does not use end-to-end encryption

Zoom used its own definition for end-to-end encryption(new window) (E2EE), one that is likely to mislead many of its users. Despite both Zoom’s website(new window) and its security white paper(new window) claiming calls that use “computer audio” are end-to-end encrypted, The Intercept found that Zoom only uses transport layer security (TLS) encryption, the same encryption that protects all websites that use HTTPS.

TLS encryption protects Internet connections from being eavesdropped on by third parties, but in this case, it does not protect the data from Zoom itself. This is different from E2EE services like Proton Mail. With true E2EE, a message (or video chat) is encrypted on a user’s device and then cannot be decrypted until it reaches the recipient’s device. No one can decrypt or access unencrypted data between the two end users.

A Zoom spokesman clarified that E2EE to Zoom means, “the connection [is] encrypted from Zoom end point to Zoom end point.” Here “end point” refers to the Zoom server, not the Zoom app. This is not true E2EE.

In response to this reporting and the widespread confusion, Zoom put out a blog post(new window) that acknowledged, “there is a discrepancy between the commonly accepted definition of end-to-end encryption and how we were using it.”

Zoom has since announced that it will make true end-to-end encryption available for all users(new window).


Online trolls have disrupted numerous online conference calls, by sharing disturbing or pornographic material using a Zoom screen share feature. This has become known as “Zoombombing,” and it is a widespread problem.

Zoom, by default, allows anyone to share their screen with the participants of a call without permission from the call’s host. If a call is public, anyone with the URL to the call can join. This has allowed malicious actors to sneak into calls using publicly shared links and then take over by sharing their screen and showing the audience offensive material.

The camera hacking bug

Last year, security consultant Johnathan Leitschuch(new window) discovered that Zoom set up a local web server on a user’s Mac device that allowed Zoom to bypass security features in Safari 12. This web server was not mentioned in any of Zoom’s official documentation. It was used to bypass a pop-up window that Safari 12 would show before it turned on your device’s camera.

However, this remote web server was also not adequately secured. Pretty much any website could interact with it. The result was that Zoom allowed malicious websites to take over your Mac’s camera without ever alerting you.

This led Electronic Privacy Information Center to file an FTC complaint(new window) against Zoom, alleging that Zoom “intentionally designed its web conferencing service to bypass browser security settings and remotely enable a user’s web camera without the knowledge or consent of the user.”

While Zoom has since removed these remote web servers(new window), its cavalier approach to getting user permission and its repeated disregard for security and privacy concerns in the pursuit of convenience raise serious questions about trust. 

How you can protect your data

As Zoom becomes the standard video conferencing tool, there are some steps you can take to keep your data safe.

  • Do not use Facebook to sign in: It might save time, but it is a poor security practice and dramatically increases the amount of personal data Zoom has access to. 
  • Keep your Zoom app updated: Zoom removed the remote web server from the latest versions of its apps. If you recently downloaded Zoom, there’s no need to be concerned about this specific vulnerability.
  • Prevent intruders and Zoombombing on your calls: Before you set up a public Zoom call, go to Settings and turn Screen Sharing to “Host only,” disable “Join Before Host,” disable “Allow Removed Participants to Rejoin,” and disable “File Transfers.” If practical, you should also protect your conference call with a password.

We recognize that working from home is going to require a reconfiguring of how companies, offices, and employees work. However, workers’ personal privacy should not be sacrificed in this transition.

Now that offices are closed, it is more important than ever that workers remember security guidelines. We have resources that can help you stay safe. Our IT security ebook(new window), with its email security(new window) and IT security(new window) best practices lists, can help employees maintain their security and privacy while working from home.

UPDATE March 27, 2020: This article was updated to incorporate the news that Zoom’s iOS app shares data with Facebook.

UPDATE March 30, 2020: This article was updated after Zoom removed the code that shared users’ device data with Facebook.

UPDATE April 1, 2020: This article was updated after the New York Attorney General requested security information from Zoom and a California resident filed a class action suit against the company. It also incorporates new information discovered about Zoom’s false claims regarding end-to-end encryption and new reporting on Zoombombing.

UPDATE May 4, 2020: This article was updated to show that Zoom removed its attendee attention tracking feature, which alerted the hosts of a call if you minimized or clicked away from your Zoom window for 30 seconds. It also now includes Zoom’s explanation for why it was using “end-to-end encryption” in its marketing.

UPDATE June 9, 2020: This article was updated after Zoom announced it would make end-to-end encryption available onl(new window)y(new window) for paying users(new window).

UPDATE June 25, 2020: This article was updated after Zoom backtracked from its original stance that it would only offer end-to-end encryption to paying users. It has since announced that E2EE will be available to all users, including those on a free plan.

You can get a secure email by choosing using our Free plan or upgrade to a paid version of Proton Mail.

We also provide a free VPN service(new window) to protect your privacy.

ProtonMail and Proton VPN are funded by community contributions. If you would like to support our development efforts, you can upgrade to a paid plan(new window). Thank you for your support.

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