(Pwn2Own) Apple macOS cfprefsd Time-Of-Check Time-Of-Use Privilege Escalation Vulnerability

Vulnerability Details

This vulnerability allows local attackers to escalate privileges on affected installations of Apple macOS. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the handling of file permisions. The issue results from the lack of proper locking when performing operations on an object. An attacker can leverage this in conjunction with other vulnerabilities to escalate privileges and execute code in the context of the root.

Additional Details

https://support.apple.com/en-gb/HT211170

Disclosure Timeline

• 2020-05-27 - Vulnerability reported to vendor
• 2020-05-28 - Coordinated public release of advisory

Credit

@jinmo123, @setuid0x0_, and @insu_yun_en of @SSLab_Gatech

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