Advisory Details

August 10th, 2020

(Pwn2Own) Apple macOS kextload Time-Of-Check Time-Of-Use Memory Corruption Vulnerability

ZDI-20-960
ZDI-CAN-10778

CVE ID CVE-2020-9939
CVSS SCORE 8.2, AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
AFFECTED VENDORS Apple
AFFECTED PRODUCTS macOS
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 high-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the handling of kernel extensions in kextload. 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 kernel.

ADDITIONAL DETAILS Apple has issued an update to correct this vulnerability. More details can be found at:
https://support.apple.com/en-us/HT211289
DISCLOSURE TIMELINE
  • 2020-07-23 - Vulnerability reported to vendor
  • 2020-08-10 - Coordinated public release of advisory
  • 2021-06-29 - Advisory Updated
CREDIT @SSLab_Gatech (@jinmo123, @setuid0x0_, and @insu_yun_en)
BACK TO ADVISORIES