CVE-2020-3427
Duo Authentication for Windows Logon and RDP Privilege Escalation Vulnerability
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Duo Authentication for Windows Logon and RDP Privilege Escalation Vulnerability
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.
- Record
CVE-2020-3427- CVSS 3.1
- 6.6 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N - Weakness
- CWE-280
- Updated
- 2026-11-02
EUVDEUVD-2020-24698
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.
- Record
EUVD-2020-24698- CVSS 3.1
- 6.6 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-437m-6wfg-j372
A privilege escalation vulnerability exists in the Duo Authentication for Windows Logon and RDP...
A privilege escalation vulnerability exists in the Duo Authentication for Windows Logon and RDP implementation. This vulnerability could allow an authenticated local attacker to overwrite files in privileged directories.
- Record
GHSA-437m-6wfg-j372- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-755
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2020-3427- CVSS 3.1
- 6.6 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N - CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 4.6 Medium
AV:L/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-280
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-3427 is a medium vulnerability (CVSS 6.6) in Cisco Duo Authentication For Windows Logon And Rdp, published October 14, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.31%, the 23rd percentile. No source names a fixed version.