Electron: Local race condition in Squirrel.Mac update installation on macOS

Overview

Impact

On macOS, Electron bundles the Squirrel.Mac auto-update framework, whose privileged ShipIt helper performs the final step of an update as root. A local attacker could cause that helper to overwrite a different application's files, as root, instead of the app that started the update. Exploitation requires local access to the machine.

Apps are only affected on macOS if they ship Squirrel.Mac-based auto-updates. Apps on other platforms, or that do not use Squirrel.Mac auto-updates, are not affected.

Workarounds

There are no app side workarounds, you must update to a patched version of Electron.

Fixed Versions

• 42.0.0-beta.2
• 41.10.5
• 39.8.10

For more information

If you have any questions or comments about this advisory, email us at [email protected]

Affected packages

• electron < 39.8.10
• electron >= 40.0.0-alpha.1, < 41.10.5
• electron >= 42.0.0-alpha.1, < 42.0.0-beta.2

Remediation

Upgrade to a patched release:

• electron 39.8.10
• electron 41.10.5
• electron 42.0.0-beta.2