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,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.