Microsoft uncovered a vulnerability in macOS that could allow specially crafted codes to escape the App Sandbox and run unrestricted on the system. We shared these findings with Apple through Coordinated Vulnerability Disclosure (CVD) via Microsoft Security Vulnerability Research (MSVR) in October 2021. A fix for this vulnerability, now identified as CVE-2022-26706, was included in the security updates released by Apple on May 16, 2022. Microsoft shares the vulnerability disclosure credit with another researcher, Arsenii Kostromin (0x3c3e), who discovered a similar technique independently.
We encourage macOS users to install these security updates as soon as possible. We also want to thank the Apple product security team for their responsiveness in fixing this issue.
The App Sandbox is Apple’s access control technology that application developers must adopt to distribute their apps through the Mac App Store. Essentially, an app’s processes are enforced with customizable rules, such as the ability to read or write specific files. The App Sandbox also restricts the processes’ access to system resources and user data to minimize the impact or damage if the app becomes compromised. However, we found that specially crafted codes could bypass these rules. An attacker could take advantage of this sandbox escape vulnerability to gain elevated privileges on the affected device or execute malicious commands like installing additional payloads.