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Server Application Security

Servers introduce unique security risks by exposing services to users inside and outside a network, requiring dedicated hardening measures beyond standard endpoint protection. This content covers the client-server model, secure software development lifecycle practices, network segmentation, and infrastructure-level defenses like firewalls, bastion hosts, and proxy servers.

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About this video

Servers are purpose-built to expose services to clients, whether over the internet or within an internal network, and that necessary openness is also a fundamental security liability. In a client-server relationship, the server delivers resources that client applications request and display, but each connection represents a potential attack surface. If a server is compromised and loaded with malware, every client that reaches out to it becomes a target as well — meaning server security is not just an internal IT concern but a direct factor in customer trust and organizational reputation. Keeping services available and keeping them clean are equally critical objectives. A secure software development lifecycle forms the foundation of server protection, ensuring that services move through planning, design, development, testing, and maintenance phases with security built in at every stage rather than patched on afterward. On the infrastructure side, specialized firewalls, bastion hosts, and proxy servers provide perimeter-level defense, while network segmentation isolates servers from general user traffic and separates front-end service hosts from back-end database tiers. Because a server is, at its core, an endpoint, all standard endpoint security practices apply — hardening through proper configuration, installing and maintaining appropriate security software, and continuous monitoring to detect and respond to threats before they can propagate.

What you'll learn

What's covered

Server Security

Key terms

Server
A computer or program that provides services or resources to other devices, known as clients, over a network.
Attack Surface
The total set of points in a system where an unauthorized user can attempt to enter or extract data.
Network Segmentation
The practice of dividing a network into smaller segments to improve performance and limit the spread of security threats.
Firewall
A network security device that monitors and controls incoming and outgoing traffic based on predefined security rules.
Proxy Server
An intermediary server that handles requests between clients and other servers, providing anonymity and content filtering.
Endpoint
Any device that connects to a network, including computers, smartphones, tablets, and IoT devices.
Malware
Software specifically designed to disrupt, damage, or gain unauthorized access to a system.
Software Development Life Cycle
SDLC
Software Development Life Cycle is the structured process for planning, creating, testing, and deploying software; in security, a secure SDLC integrates threat modeling, code review, and security testing at each phase to reduce vulnerabilities before release.
Bastion Host
A hardened server placed on the network perimeter that serves as a gateway to protect internal servers from external threats.
Server Hardening
The process of securing a server by applying proper configurations, installing security software, and performing ongoing maintenance and monitoring to reduce its attack surface.

Topics

Server Security Server Hardening Secure Sdlc Network Segmentation Firewalls Bastion Hosts Cybersecurity

Transcript

The Client-Server Relationship

When it comes to servers, we're probably exposing them to the outside world, or at least internally into our network. There's a bit of exposure because we need to open up services, we need to open up that application to other users. Now, this can become problematic, and for that reason we need to take some extra steps to make sure these devices are secure.

In computers, we have something called a client server relationship. On our user side here, we have the client. The client is the machine that's going to access certain services. Over here, we have a server. The server delivers these services. On the server, we have services that are running. In this case, it's a www service or a web service. And so what happens is that the client machine has an application on it. When it comes to web services, that's a browser. So they open up the browser and they access a website. What it's accessing is a service on the server, and the server delivers then the information the application is looking for or requests, and then it displays it, so that way the end user can see that.

The problem is that we are opening up a security hole with this, that this user is actually gaining access to this server, and so there's already a certain amount of openness about this, and that causes some security concerns. So there's ways that we can safeguard the server and take extra steps, because we are opening it up to the outside world.

Why This Matters Beyond Uptime

Now, protecting the server is a concern that we have for the business, because we want to make sure that the server is up and running and that other users can gain access to the service. But it goes even beyond that. Let's say if this machine was compromised and malware was put on it. Now any client that accesses this machine, it's just not a matter of whether it's up or down, but that malware can actually infect the client. So this is not only protection against our organizations and making sure our organizations are secure and that our services remain available, but it also is our reputation at stake. If people are connecting to our services and getting malware, then they're not going to come back.

Securing the Software and the Infrastructure

These services are just software that's running on the machine. So one of the steps that we need to take to protect this machine is make sure that we have a proper software development life cycle, or SDL. What a software development life cycle is is just a way of rolling out new software, but we need to make sure we do this in a secure way. So we go through the plan, design, develop, test and maintain phases of this, to deploy services that are going to be hardened services and software that are going to be secure.

But we also have to supply an infrastructure for those servers. So here is an example where we have many servers here. Well, how are we going to guard that? Well, with specialized firewalls, maybe something like a bastion host or a proxy server. There's ways that we need to protect these machines on the back end and make sure that they're not going to be compromised. As part of that, we would use network segmentation and access with this. Somehow we would put this on a separate network that's possibly alone from the rest of our devices, or maybe on a network that just has devices that are open to the outside world, or maybe we on the back end have a separate segment that connects these servers to a database.

A Server Is an Endpoint

So we still need to practice everything that we've learned up until now, to include our endpoint security. When it comes to a server, it is an endpoint. So there are built-in technologies into it that we need to make sure are protecting it. We need to make sure we harden this by going through proper configurations and installing the proper software on it. We need to go through maintenance on this. We need to go through monitoring. All the security measures that would be for an endpoint we would put on a server, because after all, a server is an endpoint.

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