The Mac App Store distribution of the Canva for Mac desktop app before 1.117.1 was built without Hardened Runtime. A local threat actor with unprivileged access could execute arbitrary code that inherits the TCC (Transparency, Consent, and Control) permissions assigned to Canva.
Weakness
During installation, installed file permissions are set to allow anyone to modify those files.
Potential Mitigations
- Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
- Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
References