A single character in a script can break a Jamf tenant's ability to update inventory (recon) completely.

This is more of an informational post that hopefully helps someone one day. I recently discovered a weird situation where if you have an Extension Attribute script that contains a particular single character it completely breaks the entire Jamf tenants ability for any Macs to update inventory.

Notice the difference in the two images. The first is my view in my script editor (CodeRunner in this case). The second is the view of the script in Jamf while editing the EA.
 

There is an odd character on the third line that appears to be an invisible backspace (apparently ctrl-H). I verified that it does show in multiple web browsers, just not in CodeRunner (does show in SublimeText).

Aside from finding the bug in the code eventually, if a script contains this character in particular, just having the script active seems to break Jamf’s ability for devices to recon. Once I enabled the script, ALL Macs started receiving the following error.

 

sudo jamf recon -verbose

verbose: Timeout: 10

verbose: Checking availability of https://foo.jamfcloud.com/...

verbose: The JSS is available.

Retrieving inventory preferences from https://foo.jamfcloud.com/...



There was an error.



     Message has no content

Once the script is disabled, everything goes back to normal. Also noticed that recon wasn’t even getting to the step of running the script (it’s in a long list of EAs) but failing immediately.

Kind of curious if there’s any other characters that can cause this particular issue. Super scary that a single character in a single script is able to break an entirely necessary major function in the entire system.