Sergey Budaev

Apr 03, 2020

Is ​Zoom safe to use? Is the company marketing and other information correct and can be trusted?

Zoom privacy and security problems

Zoom has demonstrated significant negligence with respect to cybersecurity. Additionally, the company has shown aggressive marketing campaigns and was caught at providing false information to its end users.

  • Zoom aggressively forces the user to download and install native application rather than use web browser for videoconferencing even though videoconferences will work in the web browser. This is a little suspicious. Browser-based conferences are more convenient for an occasional user and is safer due to browser sandboxing of network applications.

  • Serious security deficiency on the Apple Mac platform allowing any unauthorized remote attacker to activate web camera, connect to a conference and execute denial-of-service attack. Zoom tried to ignore and deliberately hide information about the very serious security vulnerability and was slow to fix it. ​ See here for more details, ​ and here (technical information is ​ here and ​ here). Zoom management response seem to point to quite irresponsible corporate culture.

  • More recently it appeared that Zoom was sending users' data to Facebook servers without the user's consent. This is now fixed. See ​ Vice paper ​ and this follow-up.

  • Zoom was caught at providing false and misleading information that the videoconference has "end-to-end" encryption while this was not so. Check out this. The explanation for this provided by Zoom is unsatisfactory.

  • Zoom had a serious security vulnerability that could lead to user password leak in Microsoft Windows. ​ See here for details.

  • Zoom has a strange privacy policy that, even though states that "privacy is very important to us," requires quite large collection of private user's information. There is little explanation about to why this information is collected. Unlike many other similar companies, Zoom does not release transparency report(s). See here: ​

  • Electronic Privacy Information Centre has filed complaint to FCC

    • alleging that the videoconferencing company Zoom has committed unfair and deceptive practices in violation of the FTC Act. According to EPIC, 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.
  • See more details here

  • There is a growing concern on the privacy deficiency in Zoom, for more details see ​this and ​ this. Also see The Guardian.

  • Recently SpaceX has banned Zoom because of privacy concerns, see here for details.

  • Zoom has close links with China. Even though the intellectual property, management and marketing are based in the USA, many if not most developers and engineers are bsed in China (see ​Form S-1 registration statement). This can potentially lead to serious privacy and cybersecurity issues, given the Chinese regime tightening of Internet regulation (censorship, privacy etc.). One example is ​MLPS 2.0 legislation, 2019 mandating China residents and any foreign companies unrestricted access to user data. (In China, Zoom has a network of agents acting under different names but using the same platform. )

Updates: More on Zoom problems

How to increase privacy and security of using Zoom on Linux

Sandboxing. On the Linux platform, one solution is always to run Zoom videoconferencing software only in a limited sandbox. Then, Zoom client would not have access to user's files and other processes running on the system.

  • Update: This recipe works for Zoom v. 3.5.361645.0301, but not for some later versions, e.g. 3.5.374815.0324, see update below on this.

Disable any unauthorized update/upgrade of Zoom client. Do not install Zoom software via the standard reopository. Use static tar.gz archive instead. Select Other Linux OS for installation. Uncompress the static distribution in a safe directory. Disadvantage of this is that update is only manual, check out Zoom web site for new releases and read changelog. But advantage is that zoom cannot silently install any unauthorized update or software on the system.

It also makes sense to register at Zoom with the institutional email but separate password, so Zoom does not use the main institutional login (SSO login). This might help against credentials leak in case of Zoom software vulnerability. Using the institutional email to register would ensure Zoom is registered as "licensed."

Install firejail sandboxing.

sudo apt install firejail.

  • Firejail is a SUID program that reduces the risk of security breaches by restricting the running environment of untrusted applications using Linux namespaces and seccomp-bpf. ... Firejail can sandbox any type of processes: servers, graphical applications, and even user login sessions. The software includes security profiles for a large number of Linux programs: Mozilla Firefox, Chromium, VLC, Transmission etc. To start the sandbox, prefix your command with “firejail.”

Make a configuration file for Zoom in .config/firejail/. Here is the configuration file named as the main Zoom run executable: ZoomLauncher.profile (given the running executable is ZoomLauncher):

# Note: to delete all firejail profiles for all local trusted apps
#  run sudo firecfg --clean
# ----------------------------------------------------------------
# Duplication of zoom configs in noblacklist and whitelist
# sections fixes login credentials no save problem:
noblacklist ${HOME}/.config/zoomus.conf
noblacklist ${HOME}/.zoom
include /etc/firejail/
include /etc/firejail/
include /etc/firejail/
include /etc/firejail/
whitelist ${HOME}/bin/zoom
whitelist ${HOME}/.config/zoomus.conf
whitelist ${HOME}/.zoom
whitelist ${HOME}/.cache/zoom
whitelist ${HOME}/downloads
include /etc/firejail/
caps.drop all
protocol unix,inet,inet6
# Needed for latest versions of Zoom and perhaps certain other Qt/QML apps

Now Zoom client can be started from the firejail sandbox:

firejail /path_to_safe_install_location/bin/zoom/ZoomLauncher

To make it possible to use standard graphical menus, one need to make a zoom.desktop startup file in the user's directory .local/share/applications. The Exec entry of the file must include the firejail-based startup:

[Desktop Entry]
Name=Zoom Desktop [Jailed]
GenericName=Zoom videoconferencing
Comment=Zoom Desktop Client jailed
Exec=firejail /path_to_safe_install_location/bin/zoom/ZoomLauncher %f

Firejail caveats

Firejail can start serving all user's applications in its jail, which is often too restrictive (e.g. settings are not saved).

  • To force reconfiguring all application to run in firejail do (do not do this if you are unsure) this:

    sudo firecfg

  • To disable configuring all local applications to run in jail, do this:

    sudo firecfg --clean

  • Do this (sudo firecfg --clean) if you have problems starting applications after installing firejail.

  • To check if an application is by default starting in a jail, run it from the terminal. If terminal shows several lines like Reading profile /etc/firejail/ then the application runs in a jail.

A newer version of Zoom client (3.5.374815.0324) refused to run in a jailed environment and hanged.

A workaround for running recent Zoom in jail:

add the below line env QML_DISABLE_DISK_CACHE=1

to the firejail config file.

  • QML_DISABLE_DISK_CACHE Disables the disk cache and forces re-compilation from source for all QML and JavaScript files. (from QML Documentation)

How to increase privacy and security of using Zoom on Microsoft Windows

Here is a link on sandbox in Windows 10: How to use Windows sandbox.

I have not tested how this works.

Android sandbox

For Android, one solution is to use the open source ​Shelter application, then mobile Zoom can run in a secure container.

I have been running several programs that I do not like to give access to my data within Shelter. It works fine for me.


  • Contacts (address book) are not leaked to Zoom if a separate address book is used within shelter

  • All apps can be frozen to avoid them run all the time at the background, this reduces the chances of data leaks as well as battery drain. Freezing can be done automatically, after timeout.