Corporate Network Security: How to Detect & Prevent Attacks

Corporate network security encompasses various hardware and software solutions that help manage access and protect corporate networks from an array of threats. A robust network security posture safeguards the usability and integrity of your data and protects sensitive, proprietary information. 

As your business grows and you add more users, devices, and applications, you become more vulnerable. Therefore, it’s vital that your corporate network has layered defenses on the edge and within it that keep attackers at bay. Authorized users get access, while malicious actors are stopped in their tracks. 

How a robust corporate network security system works

The first critical function of a network security system is to monitor the traffic coming in and out of your firewall. It's not enough to rely on alerts; a good security system needs to understand threats and be ready to act. If unusual activity is detected, quick action can prevent a minor issue from becoming a major breach.

Staying updated on new threats is essential for network security. Therefore, your security system needs tools that track current threat activities and vulnerabilities. Signing up for alerts from CISA to stay ahead of cyber threats can help with this.

As essential as threat detection is, it does not stop attacks. For that, your system requires robust firewall and antivirus software. These are your frontline defense that must always be in the best possible shape. A neglected defense system is an open invitation to cybercriminals.

Installing a data protection solution adds another layer of security. This acts as a safety net, protecting you from data loss if a breach occurs. Remember, network security isn't just about keeping threats out; it’s also about containment and recovery.

Types of network security threats corporate organizations face

Malware

Malware includes viruses, worms, ransomware, and spyware. Ransomware attacks like the infamous WannaCry can lock down critical systems and demand payment for access. These attacks can paralyze operations in no time, leaving companies scrambling to restore functionality.

Phishing

Phishing is where cybercriminals send deceptive emails that appear legitimate, tricking employees into divulging sensitive information. An instance of this is when an employee receives an email seemingly from your CEO, requesting a wire transfer. If they fall for the trap, the company may take a massive financial hit.

Insider threats 

Insider threats come from employees, contractors, or anyone with access to the corporate network. Insiders can unintentionally cause harm by falling for phishing scams or mishandling data. 

They might also act maliciously, like in a case where a disgruntled employee leaks confidential information to a competitor. Trusting your team is crucial, but so is monitoring access and behavior.

Denial of Service (DoS) and Distributed Denial of Service (DDoS).

These attacks disrupt services by overwhelming network resources. For instance, if your web servers are hit by a DDoS attack, your systems may experience significant downtime. This highlights the need for robust defenses like traffic analysis and load balancing to mitigate such attacks.

Man-in-the-middle (MitM) attacks 

MitM attacks involve an attacker intercepting and possibly altering communication between two parties. Imagine logging into a corporate email account over an unsecured public Wi-Fi, only to have someone eavesdrop on the entire conversation. Implementing encryption and using secure connections help defend against these attacks.

Advanced persistent threats (APTs)

APTs are stealthy and prolonged cyberattacks. Attackers infiltrate the network and remain undetected for extended periods, gathering sensitive data. 

These attacks do not happen often, but when they do, they are devastating. The infamous case of the APT1 group comes to mind. That attack systematically stole massive amounts of data from various organizations over several years.

Zero-day exploits

These involve attacks on vulnerabilities that the software developer isn’t even aware of yet. Zero-day exploits are particularly challenging because there's no patch available at the time of the attack. Companies often employ intrusion detection systems to identify unusual activities that might indicate a zero-day exploit.

Tools for detecting attacks and enhancing network security

Firewalls

Firewalls are the gatekeepers of your corporate network that monitor incoming and outgoing traffic. They decide which traffic to allow and block based on a set of predefined security rules. 

One of the simplest types is the proxy firewall. This type acts as a gateway between your internal network and external networks for specific applications. It provides content caching and additional security by preventing direct connections from outside. However, it can sometimes slow things down and limit the applications you can use.

The more traditional type is the stateful inspection firewall which keeps track of the state of active connections and makes decisions based on the context of the traffic. It looks at the state, port, and protocol to decide whether to allow or block traffic.

Unified Threat Management (UTM) firewalls take things a step further by combining stateful inspection with additional security functions like intrusion prevention and antivirus in a user-friendly package. 

Next-generation firewalls (NGFWs) are what you need to tackle modern threats like advanced malware and application-layer attacks. According to Gartner, these firewalls should have integrated intrusion prevention systems, application awareness, and advanced threat detection capabilities. 

For even more advanced protection, consider threat-focused NGFWs. These firewalls provide all the features of a traditional NGFW but go further by offering real-time threat detection and remediation. They help you identify which assets are most at risk, react quickly to attacks, and reduce the time it takes to clean up after a threat.

Virtual firewalls are another crucial component of network security, especially for networks that span both physical and virtual environments. Deployed in private or public clouds like AWS or Google Cloud, these firewalls secure traffic across different network segments. 

Cloud-native firewalls are the latest innovation, designed to secure applications and workloads at scale in cloud environments. They provide benefits like automated scaling, multi-tenant capability, and smart load balancing, making them ideal for dynamic, modern infrastructures.

Intrusion Detection and Prevention Systems (IDPS)

Intrusion Detection and Prevention Systems (IDPS) constantly monitor network traffic to detect suspicious activities and halt any potential threats. Think of an IDPS as a security guard at the entrance of your company. It checks every packet of data entering and leaving your network, ensuring nothing malicious slips through.

Some IDPSs can detect intrusions by analyzing network traffic in real time. If someone tries to sneak in malware through a phishing email, they can instantly flag it. This immediate detection helps you to act swiftly, mitigating damage before it spreads. 

Other intrusion detection and prevention systems not only detect threats but also take proactive measures to block them. Suppose a hacker attempts to exploit a vulnerability in your server, the IDPS can identify the unusual activity and automatically block the IP address of the hacker, stopping the attack before it happens. 

The more advanced IDPS solutions use machine learning to identify new threats that traditional systems might miss. If a new type of ransomware appears, the IDPS can recognize patterns that signify an attack, even if it has never seen this specific ransomware before. This proactive approach is crucial for staying ahead of evolving cyber threats.

IDPS tools also provide valuable insights into your network's health. By examining the alerts generated, you can identify potential weak spots and fortify them. 

For example, if your IDPS notices repeated failed login attempts on certain servers, it might indicate a brute-force attack. You can then strengthen your password policies or implement additional authentication layers on those servers.

Signature-based detection

Signature-based detection is a classic method for spotting threats. It's a bit like having a list of known bad guys (signatures) and checking if anyone on that list is trying to get in. It looks simple but it’s pretty effective for known threats.

Here's how it works. Imagine you have a database of signatures, which are essentially unique patterns or strings of data that match malicious activity. Whenever data packets flow through the network, your security systems compare them to this database. If there's a match, it triggers an alert.

This approach works well for catching known viruses, worms, and other forms of malware. But here's where it gets interesting. Signature-based detection isn't just for malware. It can also identify network intrusions. 

For instance, if there's a known pattern for an SQL injection attack, your system can spot this by looking for that specific sequence of commands. Or, consider phishing emails. If there's a pattern in the subject line or the body text—something that's been flagged before—the system can catch it before it even hits the inbox.

However, there are some downsides. The biggest one is that signature-based detection only works for known threats. If a cybercriminal comes up with a new trick that hasn't been captured in a signature, it can slip right through. 

This is often referred to as the zero-day problem. That's why you should pair signature-based detection with other methods, like anomaly-based detection, to cover all our bases.

Anomaly-based detection

Unlike traditional methods that rely on known signatures, anomaly-based detection focuses on spotting unusual patterns. It establishes what's "normal" for network traffic and then flags anything that deviates from this baseline.

This approach is especially effective against zero-day attacks that signature-based systems aren’t equipped to deal with. Let's say you set up an anomaly-based system on your corporate network. One day, it picks up an unusual spike in outbound traffic from a server that typically only handles internal data. 

That could be an indication of data exfiltration, perhaps by a new strain of malware. You wouldn't have caught this with signature-based detection because the malware is brand new and unknown.

Another example is user behavior analytics. If an employee suddenly starts accessing large volumes of sensitive data at odd hours, that's an anomaly. Your system would flag this unusual behavior, allowing you to investigate further. 

The beauty of anomaly-based detection is its adaptability. As your network traffic evolves, so does the baseline. If an event forces a team member who used to work from company offices to work remotely, the system can adjust to this new pattern of normalcy. In a different instance, if an employee's VPN connection suddenly originates from a foreign country known for cyber threats, you get an alert.

While false positives can occur, where the system flags benign activities as threats, these can be fine-tuned over time. The key is to balance sensitivity and specificity. This often involves a bit of trial and error, but the benefits far outweigh the initial hiccups.

Virtual private networks (VPNs)

VPNs are like encrypted tunnels that connect remote employees to your internal network. This means that when someone is working from home or a coffee shop, their connection to your network is protected from prying eyes.

VPN solutions ensure that all communications by remote team members are secure, especially when they involve sensitive client data. They are particularly essential when remote team members connect from public Wi-Fi, which is notoriously insecure. A VPN encrypts their data, making it nearly impossible for hackers to intercept their information.

VPNs also play a critical role in securing mobile devices. If a team member loses their phone while traveling, a VPN that requires multi-factor authentication will make it hard for whoever obtains the phone to log into your systems with it. This added layer of security will ensure that your data remains safe.

A VPN is also indispensable where you have to provide temporary network access to a contractor. You don’t have to give them full access to your internal systems, so you can use a VPN with specific access controls. This way, the contractor could only access the files and applications they need for their work. It’s a perfect balance between accessibility and security.

Implementing a VPN also helps you to comply with industry regulations. In the healthcare sector, for example, protecting patient data is paramount. Using a VPN ensures that any remote access to patient records is secure and compliant with laws like HIPAA. This isn't just about avoiding penalties; it's about maintaining trust.

Network security policies and procedures

Having solid security policies and procedures is essential for keeping your corporate network secure. These policies are the rulebook that everyone in the company has to follow. They ensure everyone is on the same page and knows how to protect your digital assets from potential threats.

The most important of these are your access control policies. These are all about who gets to see what. For example, not everyone in the company needs access to sensitive financial data or customer information. 

So, using role-based access controls (RBAC) ensures that employees only have access to the information they need to do their jobs. This way, if someone’s account gets compromised, the damage is limited.

Next, you need to think carefully about your password policy. Weak passwords are a hacker's best friend, so make sure everyone uses strong, complex passwords. 

Passwords with at least twelve characters and that include a mix of letters, numbers, and special characters are harder for malicious actors to guess. You can also encourage the use of password managers in your team. 

Then, there's the matter of network monitoring. You don’t just put these policies in place and forget about them. You must have policies for constantly monitoring your network for unusual activities.

Another crucial part of your network security apparatus is your data encryption procedure. Ensure that any sensitive data being transferred across the network is encrypted. So, if cyber criminals intercept the data, they can't make sense of it without the decryption key.

You also need a clear incident response plan. This is your go-to guide for when things go wrong. If your network is breached, you need to act fast. Therefore your incident response plan must clearly outline the steps to take, who to contact, and how to contain the damage. 

Lastly, you must have a policy on employee training. The best network security policies in the world won't help if your team doesn’t understand them.

Employee training on security protocols should be an ongoing effort. Encourage a “neighborhood watch” approach where employees immediately  report suspicious activities, such as unexpected login issues.

Regular network security audits and assessments

Regular audits and updates are critical for a corporate network that stands ready to defend your systems at all times. You must be able to catch vulnerabilities before they become serious threats, especially because the cybersecurity landscape is always changing. Your policies can’t stay static. 

Perform regular audits to check for compliance and identify any weaknesses. If you find something that needs fixing, update your policies accordingly. This has to be a continuous process.

An audit is essentially a thorough examination of your network's security measures. It looks at everything from firewall configurations to employee access rights. 

For example, during an audit, you might discover that a former employee still has access to sensitive areas. That's a red flag. Once you identify that security gap, you revoke their access immediately.

Incorporating penetration testing into your audits is another effective strategy. You can hire ethical hackers to test your defenses. These experts will try to breach your network just like a real attacker would. If they find a way in, they document the vulnerabilities and recommend fixes.

Software updates are also paramount for maintaining a secure corporate network. Audits are a good time to ensure all systems are running the latest versions. Outdated software often has known vulnerabilities, so you must regularly update your security tools to their latest versions.

When you do your security audits, it’s also crucial to document your findings and the actions you took. This documentation will help you track your progress and provide evidence of due diligence in case of an actual security incident. You can also review past reports to identify recurring issues and address them more effectively.

Patch Management

Software and hardware vendors constantly find and fix new security flaws. If you don't keep up with these patches, your network becomes an easy target.

You need to establish a regular patch schedule. While it's tempting to apply patches whenever we have time, it’s a risky game. A regular schedule ensures you don't miss critical updates. 

Designate a specific day every month to review and apply updates. Microsoft, for example, has Patch Tuesday, a day it releases its patches. You can make such a day a good benchmark for your own schedule.

Of course, not all patches are created equal. Some are minor, affecting non-critical systems, while others address severe vulnerabilities. Hence, you should prioritize patches based on the severity of the issue. 

For instance, if a patch addresses a zero-day exploit, it should be applied immediately, even if it’s out of your regular schedule. On the other hand, a patch fixing a minor graphical glitch can wait until the next scheduled update.

Before applying any patch, you must test. You don’t want to deploy an update that might break your systems. Set up a testing environment that mimics your production network as closely as possible. Apply the patch there first and monitor it for any issues.

Automation tools can make your patch management process smoother. They can streamline the download and deployment of patches. Some can also provide detailed reports on which systems have been updated and which ones need attention. These tools save time and reduce the chance of human error.

Communication is also key in patch management. Inform everyone in the organization about upcoming patches, especially if they might impact their work. Notifying users in advance helps to avoid confusion that might cause you to miss important patches. Create a clear and concise communication plan that outlines the details of the patch, the expected downtime, and any actions users need to take.

Finally, keep records of all patches you have applied. Documentation helps you track what changes were made and when. If a patch causes problems down the line, you will have a reference point to troubleshoot. You can use a simple spreadsheet to log patch details, including the date, the system affected, and the nature of the update.

The importance of secure network design

A poorly designed network is a cybercriminal’s best friend. Consider the defense-in-depth strategy when designing or updating your network. The strategy calls for multiple layers of defense to protect your most important asset—your data. Instead of just one tall wall, you will have multiple zones, each with its defenses.

Segmentation and segregation

Segmentation and segregation break up your network into smaller, manageable pieces. This style of network design significantly reduces the risk of a widespread breach. If a subnetwork is breached, the attacker doesn’t get easy access to the entire network. 

For example, your guest WiFi should be on a different subnet from your internal business network. This way, visitors can use the internet, but they can’t peek into your company’s sensitive information.

Firewalls play a critical role in segmentation, too. You can set rules that only allow specific types of traffic between segments. Imagine you have a database server and a web server. The database server should only communicate with the web server and nothing else. 

A firewall ensures that the database server isn’t accessible to other parts of the network unnecessarily, reducing exposure to potential threats. It ensures that specific traffic can only communicate with designated zones through secure gateways.

Demilitarized Zones (DMZ)

A demilitarized zone (DMZ) is a buffer zone between the internal network and the outside world. It provides an extra layer of security by segregating public-facing services from your private internal network, which keeps external threats at bay while still allowing necessary interactions.

You can set up the DMZ to host services that need to be accessible from the internet, like your company website, email servers, and FTP servers. This way, even if these servers get compromised, the attacker doesn't gain direct access to your internal network and your sensitive systems.

You can also use firewalls to control traffic between the DMZ and your internal network. These firewalls are strict. They only allow specific, necessary traffic flows. 

For example, if your web server in the DMZ needs to pull data from a database on the internal network, the firewall rules ensure that only the required data port is open. Everything else is blocked. This minimizes exposure to potential threats.

Moreover, monitoring and logging are critical in the DMZ. You can keep a close eye on traffic patterns and access attempts. Any unusual activity, like repeated failed login attempts or unexpected data transfers, triggers alarms and prompts further investigation.