Advisory Details

September 10th, 2020

Microsoft Excel XLS File SST Record Out-Of-Bounds Write Remote Code Execution Vulnerability

ZDI-20-1133
ZDI-CAN-11446

CVE ID CVE-2020-1594
CVSS SCORE 7.8, AV:L/AC:L/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. When parsing a Shared String Table (SST) record, the process does not properly validate user-supplied data, which can result in a write past the end of an allocated buffer. 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://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1594
DISCLOSURE TIMELINE
  • 2020-07-10 - Vulnerability reported to vendor
  • 2020-09-10 - Coordinated public release of advisory
CREDIT kdot
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