LogonUser API crashing the LogonUI.exe in some of the user machines, causing a black screen issue.

Question

• The issue occurs when one of the user using our MFA agent application, logs in into the windows machine. Our application uses both managed and unmanaged code and we use LogonUser API for logging into the machine.
• Initial checks indicated that logonUI.exe crashes causing this black screen issue.
• Deep analysis shows that: -LogonUI.exe is crashing with the error code c000374 which translates to STATUS_HEAP_CORRUPTION / A heap has been corrupted. -The machine is experiencing the crash of LogonUI.
• Issue occurs on 2.1.5.55 and even after upgrading to 2.2.1 same issue appears.
• Tested logoff/logon and same behavior occurs:  customers enter wind. username & password then hit enter,  the screen turns black, so they press alt+ctrl+del and re enter wind username & password. After 3 times, user was prompt for RSA challenge screen.
• Attaching the screenshot of the crash dumps to get an expert analysis on this and any feedback on the above API and why should it crash for very few users.
• If needed I will share the entire dump into a onedrive folder.
• Dump1.PNG
• Dump2.PNG

Answer 1

Hello

For heap corruption, we may need to enable heap tracing.

Here is a link for reference:

Debugging Heap corruption with Application Verifier and Debugdiag - Microsoft Community Hub

The forum resource is limted to troubleshooting present issue, it is recommended to open a ticket for more resoures to troubleshooting present issue.