macOS App Management protection is still a joke

Three years ago, I disclosed an unfixed vulnerability in the macOS App Management feature, which you can see in the Privacy & Security section of System Settings. App Management is supposed to protect the integrity of notarized apps installed on your Mac by requiring your permission to modify them. By default, only the developer of an app, as determined by its code signing certificate, is allowed to modify the app without your explicit consent; I assume this developer exception is for automatic software update mechanisms. You can add further exceptions via the System Settings pane: “Allow the applications below to update or delete other applications.” At some point in time, without notifying me and apparently without crediting me, Apple fixed my vulnerability. I’ll talk about the fix a bit later in this blog post. First, however, I want to talk about the findings of another developer, Mysk. They found that a maliciously crafted app can modify another app on your Mac simply by deleting…