What is Brute Force – Remote Access Systems This is a threat that attacks (Virtual Private Networks (VPNs), remote logon systems, or network in general) using trial-and-error to obtain user credentials or use credentials purchased on the dark web marketplaces to gain unauthorized access to systems.   This can also be called exhaustive search. It is a cryptographic hack that relies on guessing possible combinations of a targeted password until the correct password is discovered. The longer the password, the more combinations that will need to be tested.