YubiKey Manager Privilege Escalation Let Attacker Perform Admin Functions

YubiKey Manager GUI on Windows before version 1.2.6 has a vulnerability that could allow an attacker to escalate privileges.

Due to a limitation in Windows, it requires administrator privileges to interact with FIDO authenticators. 

An attacker can exploit this by tricking a user into running the YubiKey Manager GUI with administrator rights.

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Once elevated, any web browser windows opened by the program might inherit these privileges, potentially allowing for more impactful browser-based attacks. 

The YubiKey Manager GUI on Windows has a vulnerability allowing privilege escalation, in which running the Manager as Administrator opens subsequent browser windows launched by the program with elevated privileges as well.

A local attacker could use it to gain administrator access and perform malicious actions, and some browsers, like Edge, have implemented safeguards against this, highlighting a potential security risk. 

Details Of The Issue:

YubiKey Manager GUI, a tool for managing YubiKey features like FIDO, OTP, and PIV, can launch the default browser under certain conditions requiring user interaction and isn’t automatic.

On Windows, interacting with YubiKey’s FIDO functionality requires administrator privileges due to Microsoft’s OS limitations.

Consequently, running it with administrator privileges might also elevate any browser window it opens, depending on the browser, creating a vulnerability for attackers to potentially escalate local attacks and worsen browser-based attacks by exploiting these elevated privileges. 

The YubiKey Manager GUI versions before 1.2.6 have a security vulnerability on Windows machines that don’t use Edge as the default browser. 

The vulnerability arises because Windows requires administrator privileges to interact with FIDO authenticators, and the YubiKey Manager GUI might be running with these elevated permissions on vulnerable systems. 

Other operating systems are unaffected, but avoiding running YubiKey Manager GUI with administrative privileges is recommended even on those platforms. 

Check the application’s “About” menu to confirm the YubiKey Manager GUI version and update to 1.2.6 or later to address this security issue. 

Yubico identified a vulnerability in the YubiKey Manager GUI that allows privilege escalation on Windows if run as an administrator. A local attacker could exploit this to gain administrator access and potentially perform malicious actions through browser windows opened by it.

It also recommends updating to the latest version or running the YubiKey Manager GUI as a non-privileged user, including using Microsoft Edge as the default browser due to its built-in protections, wherein vulnerability is rated as high with a CVSS score of 7.7.

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