A recently patched vulnerability in macOS, dubbed “Migraine” by Microsoft, allowed attackers with root access to bypass a kernel-level security feature that typically prevents unauthorized modification of protected files and folders on Mac computers.
For the past decade, Apple has employed System Integrity Protection (SIP) to limit malware damage by restricting root access to the filesystem.
Apple addressed the vulnerability, identified as CVE-2023-32369, in its mid-May security updates, which also resolved actively exploited zero-day flaws in the mobile browser rendering engine.
While SIP limits root access to critical parts of the operating system, exceptions are granted for tasks like operating system updates, creating opportunities for hackers to circumvent this protection.
By bypassing SIP, attackers could install rootkits, create persistent malware, and expand their attack surface without detection by antivirus or Apple’s Endpoint Security kernel monitoring system. Microsoft researchers discovered that the vulnerability leverages entitlements, which allow child processes to inherit a SIP bypass entitlement built into the operating system.
The exploitation involves triggering the systemmigrationd daemon, responsible for data migration between computers, to pass the bypass entitlement to child processes. Typically, this requires using the Migration Assistant utility and signing out of the system, but researchers found that automation could be achieved through the Setup Assistant program that appears after a fresh macOS installation.
In addition to loading undetectable malware, attackers could exploit this vulnerability to replace the Transparency, Consent, and Control database, granting unauthorized access to private data and peripherals.
