One of my favorite talks from this year's BlackHat DC was Ryan Kazanciyan's & Sean Coyne's "The Getaway" talk on data exfiltration.
Everyone should check out the slides and the whitepaper although the slides are better with the case studies and the diagrams. When you check out the slides I encourage you to think about your last pentest and:
1. could your pentest shop emulate an attacker of the level in the case studies.
2. did you or they try to scope the test in order to test things like this...aka do a Full Scope test.
3. if you aren't letting your pentesters go after your network like this how do you think YOUR network will hold up against someone that knows what they are doing?
If you ARE a pentester when was the last time you got the time and scope to do something on the order of these attacks and post exploitation activities from the case studies?
We are getting great at catching our penetration testers (video) but still horrible at catching bad guys. Rather than draining your corporate bank account to have some shop come in and help you clean up your mess and you've discovered someone stealing everything you own... 1. pick a Full Scope shop that can emulate advanced attackers and not just script kiddies with a checkbook and 2. train like you fight, open the scope for your test, give your testers time to conduct a REAL test, and let your pentesters go after it like a real bad guy would.
Instead of making your testers "test' that same 500 hosts out of 10,000 hosts with no client-sides or user interaction allowed...ask, make, force, them to conduct an end-to-end test of the expensive black boxes you have sitting in the rack, your user education, your network segmentation, and your NOC/SOC's ability to test and respond to attacks. Better to find out you suck during your test instead of when someone is stealing everything that makes you money.
Train like you fight.