Permission denied WMI error in Nagios - Fix it Now ?

Some WMI operations in Nagios, do require that the account run as an administrator. 

Here at Ibmi Media, as part of our Server Management Services, we regularly help our Customers to perform related Windows queries.

In this context, we shall look into how to resolve this Windows error.

Main cause for Nagios "Permission denied WMI error" ?

At the first instance, we might experience this error message even though the plugin tests are successful in a terminal session:

This below text indicates an error message:

UNKNOWN – Permission denied when trying to store the state data. 
Sometimes this happens if you have been testing the plugin from the command line
as a different user to the Nagios process user. You will need to change the permissions on the file or remove it. The actual error text is:
can’t create /tmp/cwpss_checkcpu__1025143___.state: Permission denied at /usr/local/nagios/libexec/check_wmi_plus.pl line 246

A very common problem that occurs is when we have been experimenting with a new command at the command line as the root user and it works fine.

However, when we create the service in Nagios, it shows the error message.

Basically, the reason why is that the plugin stores temporary files in the /tmp/ directory and updates them each time it is run.

If the first time we executed that check as the root user, then later on the nagios user will not have permission to update the file.

How to fix Nagios "Permission denied WMI error" ?

To resolve "permission denied" WMI error, apply the steps provided below:

1. Check the permissions of the files with this command:

$ ls -ls /tmp/*.state

Here we can see that the root user/group is the owner of the file:

$ -rw-r–r– 1 root root 91 Apr 24 16:10 /tmp/cwpss_checkcpu__1025143___.state

2. The simplest option is to delete the files with this command:

$ rm -rf /tmp/*.state

3. After Nagios executes the WMI service command, we can see that the nagios user/group is the owner of the file:

$ -rw-rw-r– 1 nagios nagios 105 Apr 24 16:24 /tmp/cwpss_checkcpu__1025143___.state


[Need urgent help with fixing Windows error? We are here for you. ]


This article covers methods to fix Nagios error WMI Remote "Access Denied". Basically, Nagios supports WMI monitoring, which provides admins with a simple method of monitoring their Windows servers and workstations without having to install or configure agents. 

How to fix DCOM permission ?

  • Open Dcomcnfg.
  • Expand Component Service -> Computers -> My computer.
  • Go to the properties of My Computer.
  • Select the COM Security Tab.
  • Click on "Edit Limits" under Access Permissions, and ensure "Everyone" user group has "Local Access" and "Remote Access" permission.
  • Click on the "Edit Limit" for the launch and activation permissions, and ensure "Everyone" user group has "Local Activation" and "Local Launch" permission.
  • Highlight "DCOM Config" node, and right click "Windows Management and Instruments", and click Properties.
  • <Please add the steps to check Launch and Activation Permissions, Access Permissions, Configuration Permissions based on the default of Windows Server 2008>.

How to fix Permission for the user to the WMI namespace ?

  • Open WMImgmt.msc.
  • Go to the Properties of WMI Control.
  • Go to the Security Tab.
  • Select "Root" and open "Security".
  • Ensure "Authenticated Users" has "Execute Methods", "Provider Right" and "Enable Account" right; ensure Administrators has all permission.

How to Verify WMI Impersonation Rights?

  • Click Start, click Run, type gpedit.msc, and then click OK.
  • Under Local Computer Policy, expand Computer Configuration, and then expand Windows Settings.
  • Expand Security Settings, expand Local Policies, and then click User Rights Assignment.
  • Verify that the SERVICE account is specifically granted Impersonate a client after authentication rights.