Users of Zoom on Macs should update the app, after the company issued a patch to fix a security flaw that could allow an attacker to take over their computers.

The fix will eventually roll out automatically, but users can and should install it immediately upon opening the application by clicking on Zoom.us in the menu bar at the top left of the screen and then selecting “check for updates”.

Discovered by an independent security researcher, Patrick Wardle – whose brother Jeremy invented the popular game Wordle – the vulnerability was first presented at the Def Con hacking conference in Las Vegas last week.

It targets the Zoom installer, which the company uses to enable frictionless automatic updates. In order to make the user journey simpler, the installer continues to run in the background from the moment a user first installs zoom, and does so with “superuser” privileges, allowing it to change anything about the computer.

Normally, the company tries to ensure that is safe by limiting the installer to only operate on code that has been cryptographically signed by Zoom, but the bug discovered by Wardle means that an attacker could trivially bypass that protection and convince the installer to load and run any malware they want.

It is not the first time Zoom’s focus on frictionless use has led to a security hole. In April 2020, when pandemic remote working led to a 500% increase in daily traffic to the Zoom download page, some critics said the company’s software was “a privacy disaster” and even malware.

The company’s desire to be the easiest way of joining video calls has led it to seek to bypass security measures that protect a user’s computer. Notoriously, in 2019 Zoom installed a hidden web server on user devices, to try to enable single-click joining of calls, while in 2020 a bug was discovered that let attackers turn a Mac into a remote spying device. Zoom also claimed that it used end-to-end encryption to protect calls, before admitting that it did no such thing.