CVE-2021-1492

The Duo Authentication Proxy installer prior to 5.2.1 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 Duo Authentication Proxy installer, cause Denial of Service (DoS) by deleting file(s), or replace system files to potentially achieve elevation of privileges. This is only exploitable during new installations, while the installer is running, and is not exploitable once installation has finished. Versions 5.2.1 of Duo Authentication Proxy installer addresses this issue.

Weakness

The product, when opening a file or directory, does not sufficiently handle when the file is a Windows shortcut (.LNK) whose target is outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.

Affected Software

Potential Mitigations

• Follow the principle of least privilege when assigning access rights to entities in a software system.
• Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

References

• https://help.duo.com/s/article/6789