Advisory Details

December 11th, 2020

Microsoft Excel XLS File Parsing Integer Signedness Remote Code Execution Vulnerability

ZDI-20-1425
ZDI-CAN-11752

CVE ID CVE-2020-17128
CVSS SCORE 7.0, AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
AFFECTED VENDORS Microsoft
AFFECTED PRODUCTS Excel
VULNERABILITY DETAILS

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Microsoft Excel. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the parsing of XLS files. Crafted data in an XLS file can trigger a dereference of a user-supplied value as a pointer. An attacker can leverage this vulnerability to execute code in the context of the current process.

ADDITIONAL DETAILS Microsoft has issued an update to correct this vulnerability. More details can be found at:
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-17128
DISCLOSURE TIMELINE
  • 2020-09-25 - Vulnerability reported to vendor
  • 2020-12-11 - Coordinated public release of advisory
CREDIT kdot
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