Advisory Details

February 4th, 2021

Apple macOS CoreText TTF Parsing Out-of-Bounds Write Remote Code Execution

ZDI-21-149
ZDI-CAN-12825

CVE ID CVE-2021-1772
CVSS SCORE 7.8, (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)
AFFECTED VENDORS Apple
AFFECTED PRODUCTS macOS
VULNERABILITY DETAILS

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Apple macOS. Interaction with the CoreText library is required to exploit this vulnerability but attack vectors may vary depending on the implementation.

The specific flaw exists within the parsing of TTF fonts. Crafted data in a TTF file can trigger a write past the end of an allocated data structure. An attacker can leverage this vulnerability to execute code in the context of the current process.

ADDITIONAL DETAILS Apple has issued an update to correct this vulnerability. More details can be found at:
https://support.apple.com/en-us/HT212147
DISCLOSURE TIMELINE
  • 2021-01-08 - Vulnerability reported to vendor
  • 2021-02-04 - Coordinated public release of advisory
CREDIT Mickey Jin of Trend Micro Mobile Security Research Team
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