Undeniable, incontestable or incontrovertible.
Secure against attack; impregnable.
Something, such as a belief, that cannot be assailed.
Open to disclosing one's inner thoughts and feelings, acting in spite of one's instinct to self-preservation.
More likely to be exposed to malicious programs or viruses.
More or most likely to be exposed to the chance of being attacked or harmed, either physically or emotionally.