CVE-2020-1193: Microsoft Excel Remote Code Execution Vulnerability

Overview

Severity
High (CVSS 7.8)
CVSS Vector
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
Category
Remote Code Execution
Exploit Status
Not Exploited
Exploitation Likelihood
Less Likely
Patch Tuesday
2020-Sep
Released
2020-09-08
Last Updated
2020-09-16
EPSS Score
10.67% (percentile: 93.3%)

Description

A remote code execution vulnerability exists in Microsoft Excel software when the software fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. Exploitation of the vulnerability requires that a user open a specially crafted file with an affected version of Microsoft Excel. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) containing a specially crafted file designed to exploit the vulnerability. An attacker would have no way to force users to visit the website. Instead, an attacker would have to convince users to click a link, typically by way of an enticement in an email or instant message, and then convince them to open the specially crafted file. The security update addresses the vulnerability by correcting how Microsoft Excel handles objects in memory.

FAQ

Is the Preview Pane an attack vector for this vulnerability? No, the Preview Pane is not an attack vector. Are the updates for the Microsoft Office for Mac currently available? The security update for Microsoft Office 2016 for Mac and Microsoft Office 2019 for Mac are not immediately available. The updates will be released as soon as possible, and when they are available, customers will be notified via a revision to this CVE information.

Affected Products (13)

Other

  • 11573
  • 11574
  • 11575
  • 11762
  • 11763
  • 10753
  • 10754
  • 10734
  • 10521
  • 10522
  • 10603
  • 10601
  • 10602

Security Updates (7)

Acknowledgments

ecN4L working with <a href="https://www.zerodayinitiative.com/">Trend Micro's Zero Day Initiative</a>

Revision History

  • 2020-09-08: Information published.
  • 2020-09-16: Microsoft is announcing the availability of the security updates for Microsoft Office for Mac. Customers running affected Mac software should install the update for their product to be protected from this vulnerability. Customers running other Microsoft Office software do not need to take any action. See the Release Notes for more information and download links.