How can I access the Global Address List (GAL) via Autodiscover and the Offline Address Book (OAB)?

After authenticating via Autodiscover, use the tool `checkAutodiscover.py` to obtain the OAB URL from the Autodiscover response. Then access that URL to find the `.lzx` file corresponding to the Default Global Address. Download the `.lzx` file and decode it using `oabextract` to produce a `.oab` file containing the GAL. This method is part of the broader technique of accessing Exchange mail resources discussed in Penetration Basics - Using Exchange Autodiscover.