CVE-2024-20677: Microsoft Office Remote Code Execution Vulnerability

Overview

Severity
High (CVSS 7.8)
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Category
Remote Code Execution
Exploit Status
Not Exploited
Exploitation Likelihood
Less Likely
Patch Tuesday
2024-Jan
Released
2024-01-09
Last Updated
2024-02-23
EPSS Score
0.39% (percentile: 60.2%)

Description

A security vulnerability exists in FBX that could lead to remote code execution. To mitigate this vulnerability, the ability to insert FBX files has been disabled in Word, Excel, PowerPoint and Outlook for Windows and Mac. Versions of Office that had this feature enabled will no longer have access to it. This includes Office 2019, Office 2021, Office LTSC for Mac 2021, and Microsoft 365. As of February 13, 2024, the ability to insert FBX files has also been disabled in 3D Viewer. 3D models in Office documents that were previously inserted from a FBX file will continue to work as expected unless the Link to File option was chosen at insert time. This change is effective as of the January 9, 2024 security update.

FAQ

According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is a remote code execution? The word Remote in the title refers to the location of the attacker. This type of exploit is sometimes referred to as Arbitrary Code Execution (ACE). The attack itself is carried out locally. For example, when the score indicates that the Attack Vector is Local and User Interaction is Required, this could describe an exploit in which an attacker, through social engineering, convinces a victim to download and open a specially crafted file from a website which leads to a local attack on their computer. According to the CVSS metric, successful exploitation of this vulnerability could lead to total loss of confidentiality (C:H), integrity (I:H), and availability (A:H). What does that mean for this vulnerability? An attacker who successfully exploits this vulnerability could perform a remote attack that could enable access to the victim's information and the ability to alter information. Successful exploitation could also potentially cause downtime for the targeted environment. 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 2021 for Mac currently available? The security update for Microsoft Office 2021 for Mac is not immediately available. The update will be released as soon as possible, and when it is available, customers will be notified via a revision to this CVE information. How do I get the updated app? The Microsoft Store will automatically update affected customers. Alternatively, customers can get the update immediately; see here for details. It is possible for customers to disable automatic updates for the Microsoft Store. The Microsoft Store will not automatically install this update for those customers. Customers using the Microsoft Store for Business and Microsoft Store for Education can get this update through their organizat

Affected Products (8)

Apps

  • 3D Viewer

Microsoft Office

  • Microsoft Office 2019 for 32-bit editions
  • Microsoft Office 2019 for 64-bit editions
  • Microsoft 365 Apps for Enterprise for 32-bit Systems
  • Microsoft 365 Apps for Enterprise for 64-bit Systems
  • Microsoft Office LTSC for Mac 2021
  • Microsoft Office LTSC 2021 for 64-bit editions
  • Microsoft Office LTSC 2021 for 32-bit editions

Security Updates (2)

Acknowledgments

<a href="https://www.notion.so/dong-uk-kim-91de2ceb59c44c6ea7533b0e8b2e35af">Kim Dong-Uk (@justlikebono)</a>, HAO LI of VenusTech ADLab, Anonymous <a href="https://www.zerodayinitiative.com/">Trend Micro Zero Day Initiative</a>

Revision History

  • 2024-01-09: Information published.
  • 2024-01-16: 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.
  • 2024-02-13: In the Security Updates table, added 3D Viewer as it is affected by this vulnerability. In addition, added an FAQ to explain how customers can get the 3D Viewer update.
  • 2024-02-23: Updated the Executive Summary with information that the ability to insert FBX files has also been disabled in 3D Viewer as of February 13, 2024. This is an informational change only.