Security and compliance are now the most important aspects of any IT project as the legal and reputational risks are large enough to gravely damage or even completely destroy a company.
I am CISSP certified and have extensive Linux hardening and penetration testing experience and can help to review and secure your systems.
There are several phases in securing a system and its workload(s).
Probe for internal and external weaknesses
Close as many backdoors and reduce the attack surface as much as possible
Persephone BV. can help you to both understand where the weakness are located, and to produce a plan to close these holes.