Advisory Details

December 15th, 2016

Apple OS X WindowServer _XSetDictionaryForCurrentSession Type Confusion Privilege Escalation Vulnerability

ZDI-16-639
ZDI-CAN-3773

CVE ID CVE-2016-4638
CVSS SCORE 4.4, AV:L/AC:M/Au:N/C:P/I:P/A:P
AFFECTED VENDORS Apple
AFFECTED PRODUCTS OS X
VULNERABILITY DETAILS


This vulnerability allows local attackers to execute arbitrary code on vulnerable installations of Apple OS X. 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 CoreGraphics module. The issue lies in the failure to properly validate user-supplied data which can result in a type confusion condition. An attacker can leverage this vulnerability to escalate privileges under the context of WindowServer.
ADDITIONAL DETAILS Apple has issued an update to correct this vulnerability. More details can be found at:
https://support.apple.com/en-us/HT206903
DISCLOSURE TIMELINE
  • 2016-06-14 - Vulnerability reported to vendor
  • 2016-12-15 - Coordinated public release of advisory
CREDIT e048b7039acc9483d42ca9ef197bd909
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