CVE-2020-3427: Duo Authentication for Windows Logon and RDP Privilege Escalation Vulnerability

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-10-14 · updated 2026-06-17
Weakness: CWE-280

Description

The Windows Logon installer prior to 4.1.2 did not properly validate file installation paths. This allows an attacker with local user privileges to coerce the installer to write to arbitrary privileged directories. If successful, an attacker can manipulate files used by Windows Logon, cause Denial of Service (DoS) by deleting file(s), or replace system files to potentially achieve elevation of privileges. Note that this can only exploitable during new installations while the installer is running and is not exploitable once installation is finished. Versions 4.1.2 of Windows Logon addresses this issue.

Affected products

Cisco Duo Authentication for Windows Logon and RDP: before 4.1.2 — fixed in 4.1.2

How to fix

Upgrade to a fixed version: Cisco Duo Authentication for Windows Logon and RDP 4.1.2. Check the vendor advisory for mitigations.

References

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