A Cisco User Agent can monitor the Microsoft Active Directory (AD) server and reports login and logoff activities that are authenticated by an LDAP server. A Firepower Management Center (FMC) integrates these activities with the security events it collects from a Firepower managed device. This document provides a solution to an issue when the User Agent does not start after you stop its service.
You can use the solution on this document if you notice the following symptoms with your User Agent service:
User Agent interface shows the service as Not Running.
The Windows Service Console, services.msc, shows the Cisco User Agent status as blank, and fails to start the service.
The windows event log shows an error similar to "The trust relationship between the primary domain and the trusted domain failed"
A file UserEncryptionBytes.bin is created at C:\ with zero byte in size.
The debug mode of a User Agent client shows the following error messages in the Log tab of the User Agent:
<Timestamp>,"debug"," - An error occured while fetching encryption bytes from 'C:\UserAgentEncryptionBytes.bin': The trust relationship between the primary domain and the trusted domain failed.."
<Timestamp>,"error"," - An error occured while fetching encryption bytes from 'C:\UserAgentEncryptionBytes.bin': Specified key is not a valid size for this algorithm.."
<Timestamp>,"error"," - Error connecting to 10.85.3.122: System.UnauthorizedAccessException: Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))
Step 1: Run the Microsoft Windows Services Console, services.msc. It allows you to disable or enable a Windows service.
Step 2: Right click the Cisco User Agent service and select Stop to stop the service.
Step 3: Navigate to the C: drive.
Step 4: Delete this UserAgentEncryptionBytes.bin file.
Step 5: Delete the CiscoUserAgent file, which is an SQL Server Compact Edition Database File.
Step 6: Go back into services.msc. Right click on the Cisco User Agent service, select Properties, then select Log On tab, and configure a user as an AD user login. Click Apply when done.
Step 7: On the services.msc, click Start for the Cisco Firepower User Agent for Active Directory service.
Step 8: Verify the size of the UserAgentEncryptionBytes.bin file. It should not be 0 KB.
Step 9: Add the Domain Controllers and Firepower Managmenet Center to the User Agent Client. Please be sure to add the Domain Controllers/local host before adding the Firepower Management Center to the User Agent.