Network security is an organization’s strategy and provisions for ensuring the security of its assets and all network traffic. Network security is manifested in an implementation of security hardware and software. For the purposes of this discussion, the following approach is adopted in an effort to view network security in its entirety.
The IT Security Policy is the principle document for network security. Its goal is to outline rules for ensuring the security of organizational assets. Employees today often utilize several tools and applications to conduct business productively. Policy driven from the organization’s culture supports these routines and focuses on safely enabling these tools for employees. Enforcement and auditing procedures for any regulatory compliance to which an organization is subject must be mapped out in the policy as well.
Most definitions of network security are narrowed to the enforcement mechanism. Enforcement concerns analyzing all network traffic flows and should aim to preserve the confidentiality, integrity, and availability of all systems and information on the network. These three principles compose the CIA triad:
Strong enforcement strives to provide CIA to network traffic flows. This begins with a classification of traffic flows by application, user and content. As the vehicle for content, all applications must first be identified by the firewall regardless of port, protocol, evasive tactics or SSL. Proper application identification provides full visibility into the content it carries. Policy management can be simplified by identifying applications and mapping their use to a user identity while inspecting the content at all times for the preservation of CIA.
The concept of defense in depth is observed as a best practice in network security, prescribing for the network to be secured in layers. These layers apply an assortment of security controls to sift out threats trying to enter the network: access control, identification, authentication, malware detection, encryption, file type filtering, URL filtering, and content filtering.
These layers are built through the deployment of firewalls, intrusion prevention systems (IPS) and antivirus components. Among the components for enforcement, the firewall (an access control mechanism) is the foundation of network security.
Providing CIA of network traffic flows is difficult to accomplish with legacy technology. Traditional firewalls are plagued by controls that rely on port/protocol to identify applications – which have now developed evasive characteristics to bypass the controls – and the assumption that IP address equates to user identity.
The next-generation firewall retains an access control mission, but re-engineers the technology; it observes all traffic across all ports, can classify applications and their content, and identifies employees as users. This enables access controls nuanced enough to enforce the IT security policy as it applies to each employee of the organization, with no compromise in security.
Additional services for layering network security to implement a defense-in-depth strategy have been incorporated to the traditional model as add-on components. Intrusion prevention systems (IPS) and antivirus, for example, are effective tools for scanning content and preventing malware attacks. However, organizations must be cautious of the complexity and cost that additional components may add to its network security and, more importantly, not depend on these additional components to do the core job of the firewall.
The auditing process of network security requires checking back on enforcement measures to determine how well they have aligned with the security policy. Auditing encourages continuous improvement by requiring organizations to reflect on the implementation of their policy on a consistent basis. This gives organizations the opportunity to adjust their policy and enforcement strategy in areas of evolving need.