This will give the admin user a password of admin123 (the default) and you will again be able to log in as admin user with the password admin123. Note: The above applies to Nexus 2.4 and earlier. Note: In order for this to work the XML security realm must be installed. It likely is, since it ships by default, but sometimes people remove it.
Removed all permissions from your account did you? Save it did you? Feeling a bit stupid?
Yeah, me too!
First steps
SSH to your server and stop Jenkins
Now modify the config XML
You now have two options to regain access
Yeehaw way
Turn security off and remove the <authorizationStrategy> node
Now restart Jenkins and head over to your admin UI to resecure it quick before the trolls get in.
Like a boss way
If you want to be safe and not open up a security hole at all, you can add the security permissions into the config XML manually. Just replace USERNAME with own
<authorizationStrategy class=”hudson.security.ProjectMatrixAuthorizationStrategy”>
<permission>hudson.model.Computer.Configure:USERNAME</permission>
<permission>hudson.model.Computer.Connect:USERNAME</permission>
<permission>hudson.model.Computer.Create:USERNAME</permission>
<permission>hudson.model.Computer.Delete:USERNAME</permission>
<permission>hudson.model.Computer.Disconnect:USERNAME</permission>
<permission>hudson.model.Hudson.Administer:USERNAME</permission>
<permission>hudson.model.Hudson.Read:USERNAME</permission>
<permission>hudson.model.Hudson.RunScripts:USERNAME</permission>
<permission>hudson.model.Item.Build:USERNAME</permission>
<permission>hudson.model.Item.Configure:USERNAME</permission>
<permission>hudson.model.Item.Create:USERNAME</permission>
<permission>hudson.model.Item.Delete:USERNAME</permission>
<permission>hudson.model.Item.Read:USERNAME</permission>
<permission>hudson.model.Item.Workspace:USERNAME</permission>
<permission>hudson.model.Run.Delete:USERNAME</permission>
<permission>hudson.model.Run.Update:USERNAME</permission>
<permission>hudson.model.View.Configure:USERNAME</permission>
<permission>hudson.model.View.Create:USERNAME</permission>
<permission>hudson.model.View.Delete:USERNAME</permission>
<permission>hudson.scm.SCM.Tag:USERNAME</permission>
</authorizationStrategy>
Now restart Jenkins and sit back with a smug grin.