How to run an unsigned script in Automator

I can run the well-respected perl script exiftool from the command line in Terminal and achieve the desired result, but when I incorporate it in Automator as a Service I get a generic error message and the perl script is not executed. When I look in the system.log I find: "The operation couldn’t be completed. (OSStatus error -67062.)" i.e., Code object is not signed.

Correct, exiftool is not signed, and there is nothing I can do about that. I had to bypass Gatekeeper to install it in Yosemite (10.10.5). But the script is well know in photography circles and has been used by many to edit the EXIF information in image files.

I tried to add the script or my Automator workflow to System Preferences > Security & Privacy > Privacy > Accessibility but the panel won't accept either.

Is there some way to tell Automator to accept this unsigned script or a command or switch I can put in my bash script to have it accepted?

Here is my current shell script:

for f in “$@”
do
exiftool -overwrite_original -AllDates-=1 "$f"
done

Thanks for any help.