CVE-2020-16851: OneDrive for Windows Elevation of Privilege Vulnerability

Overview

Severity
High (CVSS 7.1)
CVSS Vector
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H/E:P/RL:O/RC:C
Category
Elevation of Privilege
Exploit Status
Not Exploited
Exploitation Likelihood
Less Likely
Patch Tuesday
2020-Sep
Released
2020-09-08
EPSS Score
0.39% (percentile: 60.0%)

Description

An elevation of privilege vulnerability exists when the OneDrive for Windows Desktop application improperly handles symbolic links. An attacker who successfully exploited this vulnerability could overwrite a targeted file with an elevated status. To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and delete a targeted file with an elevated status. The update addresses this vulnerability by correcting where the OneDrive updater performs file writes while running with elevation.

FAQ

Do I need to take any action to protect myself from this vulnerability? Most customers have been protected from this vulnerability because OneDrive has its own updater that periodically checks and updates the OneDrive binary. If your network is air-gapped, you can update the binary from the link in the Security Updates table. In which situations does this vulnerability apply? This vulnerability only applies when OneDrive is installed per machine and does not apply to the default per user install. Please see Per Machine Installation for more information. Which release contains the updates to protect against the vulnerability? 20.170.0824.0001 is the minimum version. The version and all new versions are protected from this vulnerability. Does 20.201.1005.0006 include the protection for CVE-2020-16853? Yes, this version does protect against this vulnerability.

Affected Products (1)

Other

  • 11752

Security Updates (1)

Acknowledgments

Zhiniang Peng (@edwardzpeng) and Fangming Gu (@afang5472)

Revision History

  • 2020-09-08: Information published.