Perhaps data is compromised and its confidentiality is breached to outsiders. Perhaps data is altered thereby affecting the safety or well being of the owner of the data. What ensues is generally a costly security re-engineering of the system doing what should have been done initially, but for which neither the time nor money was available. The money is better spent elsewhere. It is important to note initially that once a security problem has surfaced, there is no magic security solution.
Security never relies on a single product.
The provision of network security is an application of a repeatable, many faceted methodology. Building a secure system should always begin with a formal statement of its security policy. This establishes the security playing field by defining the security objectives. The security policy yields a list of security requirements derived from it. The security design resolves the security requirements and achieves the desired level of security.