T1153 - Source

This technique has been deprecated and should no longer be used.

The source command loads functions into the current shell or executes files in the current context. This built-in command can be run in two different ways source /path/to/filename [arguments] or .This technique has been deprecated and should no longer be used. /path/to/filename [arguments]. Take note of the space after the ".". Without a space, a new shell is created that runs the program instead of running the program within the current context. This is often used to make certain features or functions available to a shell or to update a specific shell's environment.(Citation: Source Manual)

Adversaries can abuse this functionality to execute programs. The file executed with this technique does not need to be marked executable beforehand.