IT organizations manage security in different ways. Some companies have formalized security teams with board-level interest. In these companies, the security team will have firm policies and procedures that apply to network gear. Some organizations appoint a manager or director to be responsible for security with less high-level accountability. Smaller IT shops have less formal security organizations with little security-related accountability. The security guidance a network engineer receives from within their IT organization can vary widely across the industry. Regardless of the direction a network engineer receives from internal security teams, there are reasonable steps he or she can take to protect and secure the network.
Focus on the Basics
Many failures in network security happen due to a lack of basic security hygiene. While this problem extends up the entire IT stack, there are basic steps every network engineer should follow. Network gear should have consistent templated configuration across your organization. Ad-hoc configurations, varying password schemes, and a disorganized infrastructure opens the door for mistakes, inconsistencies, and vulnerabilities. A well-organized, rigorously implemented network is much more likely to be a secure network.
As part of the standard configuration for your network, pay special attention to default passwords, SNMP strings, and unencrypted access methods. Many devices ship with standard SNMP public and private communities. Change these immediately. Turn off any unencrypted access methods like telnet or unsecure web (http). If your organization doesn't have a corporate password vault system, use a free password vault like KeePass to store enable passwords and other sensitive access information. Don't leave a password list lying around, stored on Sharepoint, or unencrypted on a file share. Encrypt the disk on any computer that stores network configurations, especially engineer laptops which can be stolen or left accidentally.
To Firewall or Not to Firewall
While many hyperscalers don't use firewalls to protect their services, the average enterprise still uses firewalls for traffic flowing through their corporate network. It's important to move beyond the legacy layer 4 firewall to a next-generation, application-aware firewall. For outbound internet traffic, organizations need to build policy based on more than the 5-tuple. Building policies based on username and application will make the security posture more dynamic without compromising functionality.
Beyond the firewall, middle boxes like load balancers and reverse-proxies have an important role in your network infrastructure. Vulnerabilities, weak ciphers, and misconfigurations can leave applications and services wide open for exploit. There are many free web-based tools that can scan internet-facing hosts and report on weak ciphers and easy-to-spot vulnerabilities. Make use of these tools and then plan to remediate the findings.
Keep A Look Out for Vulnerabilities
When we think of patch cycles and vulnerability management, servers and workstations are top of mind. However, vulnerabilities exist in our networking gear too. Most vendors have mailing lists, blogs, and social media feeds where they post vulnerabilities. Subscribe to the relevant notification streams and tune your feed for information that's relevant to your organization. Make note of vulnerabilities and plan upgrades accordingly.
IT security is a broad topic that must be addressed throughout the entire stack. Most network engineers can't control the security posture of the endpoints or servers at their company but they do control networking gear and middle boxes which have a profound impact on IT security. In most instances, you can take practical, common sense steps that will dramatically improve your network security posture.