Advisory Details

May 30th, 2019

Apple macOS AMDRadeonX4000_AMDSIGLContext discard_StretchTex2Tex Double Free Privilege Escalation Vulnerability

ZDI-19-539
ZDI-CAN-8547

CVE ID CVE-2019-8635
CVSS SCORE 7.0, (AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H)
AFFECTED VENDORS Apple
AFFECTED PRODUCTS macOS
VULNERABILITY DETAILS

This vulnerability allows local attackers to escalate privileges on vulnerable 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 discard_StretchTex2Tex method of the AMDRadeonX4000_AMDSIGLContext class. The issue results from the lack of proper validation of user-supplied data, which can result in a read past the end of an allocated data structure. An attacker can leverage this in conjunction with other vulnerabilities to escalate privileges to the level 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/HT210119
DISCLOSURE TIMELINE
  • 2019-04-08 - Vulnerability reported to vendor
  • 2019-05-30 - Coordinated public release of advisory
CREDIT Lilang Wu and Moony Li of TrendMicro Mobile Security Research Team
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