Internal vs. External Vulnerability Scans What Are the Differences

Internal vs. External Vulnerability Scans: What Are the Differences?

As businesses across different industries adopt digital transformation, cybersecurity is increasingly becoming an imminent threat. Several organizations moved their legacy systems to the cloud during the pandemic to support remote working. This shift was a game-changer, enhancing flexibility and efficiency. However, it also opened up the network infrastructure to several cybersecurity risks.

Today, forward-looking enterprises deploy internal and external vulnerability scans to identify, report and fix potential network security issues. Below, we’ve highlighted the similarities, differences, and benefits of the two scanning exercises and some of the best practices to keep in mind.

Vulnerability scanning concept
Vulnerability scanning concept

What are Vulnerability Scans – Internal vs. External

Vulnerability scans are cybersecurity assessment practices used to test the network’s ability to withstand potential security threats. These scans are categorized into internal vulnerability scans and external vulnerability scans. These techniques seek to protect the business network by identifying and fixing security issues before internal or external attackers exploit them.

As the name suggests, internal vulnerability scans are performed within the internal business network to identify at-risk systems. These scans operate within the internal network firewalls and are designed to check for any threats and compliance issues within the enterprise’s IT infrastructure. 

On the other hand, external vulnerability scans are performed outside the business network. The main goal is to look for gaps in the network perimeter, IP addresses, and open internet ports. External scans often target loopholes exploited by external attackers, such as cloud-based technologies, remote networks, VPNs, outdated internet browsers, and web applications.

Before we look at some of the benefits of conducting both these scans in your organization, it’s vital first to understand that internal and external vulnerability scans play a critical role in enhancing your overall network security.  

While internal scans assume that the attacker will exploit the network from the inside, external scans take the outsider’s perspective; hence, they are conducted without access to the network.  

Why Conduct Internal Vulnerability Scans 

People with access to the organization’s network, such as employees and affiliated third parties, can easily infiltrate the system if there are open vulnerabilities in the IT infrastructure. By conducting thorough scans on the internal IT assets and systems, you can uncover several security risks from unpatched software, outdated applications to poor privilege access management practices.

Internal vulnerability scanning concept 
Internal vulnerability scanning concept

Some of the benefits of running internal vulnerability scans include:

1. Helps Prioritize Vulnerability Remediation 

Internal vulnerability scans take a proactive approach to network security management. With this technique, you can easily simulate the actions and behaviors of someone with privileged access to the critical company assets and IT network. This helps you uncover hidden vulnerabilities that the internal attacker would use to gain access into the system and move to take appropriate action immediately. 

2. Provides Insights into Patch Management 

Poor patch management practices play a critical role in helping attackers infiltrate your network. Over the years, hackers have used unpatched software to introduce malicious code into software programs. With regular internal vulnerability scans, you can quickly identify unpatched security bugs in a given software so you can take immediate action before the attackers learn about the vulnerability.

3. Helps Improve Compliance With Regulatory Requirements 

Depending on your business niche, several regulatory bodies oversee data privacy and security issues, such as PCI DSS for eCommerce businesses and HIPPA for healthcare organizations. By fixing vulnerabilities in the system, you’ll improve compliance with the regulatory requirements set by these bodies. 

Internal vulnerability scans also allow companies to mitigate security risks against network breaches, accidental and intentional attacks. Network breaches can be executed by an internal or external attacker, provided they have installed a virus or malware into the system.

Accidental attacks occur mainly due to negligence and poor security culture in the organization, for instance, using unsecured WIFI connections or falling for phishing attacks.

When performing internal vulnerability scans, it’s recommended to use credentialed and non-credentialed scan techniques. The former reveals all the vulnerabilities from network hosts, servers, and workstations, giving you a better understanding of the system’s configuration and patch management. 

However, a non-credentialed scan gives the perspective of an intruder who got into the system either through misconfigured firewalls or unsecured web servers. Both scans help expose the various forms of network vulnerabilities and threats.

Why Conduct External Vulnerability Scans 

External scans are very effective for finding and fixing possible vulnerabilities that outside attackers can exploit. The scanning is often done outside the network, targeting the IT infrastructure exposed to the outside world, i.e., the internet.

External vulnerability scanning concept 
External vulnerability scanning concept

Some of the benefits of external vulnerability scans include:

1. It Monitors Unsecured Transfer Protocols

If your network’s externally facing services aren’t secure, hackers could exploit any vulnerabilities to launch their attacks. An external scan will explore your transfer protocols for security risks and report any issues for immediate mitigation. Unsecured transfer protocols such as Telnet allow intruders to access your data and even control a portion of your network remotely.

2. It Helps Identify Servers with Outdated Services

By running an external vulnerability scan, you can easily identity security loopholes within the network structures, internet ports, and servers. A thorough assessment will also reveal significant threats posed by new devices or applications within the system. 

Some of the common vulnerabilities you should be aware of when running external scans include:

  • The use of deprecated or poorly maintained services like TLS 1.0 and 1.1 to configure servers. 
  • The use of unsecured service transfer protocols. 
  • Named vulnerabilities such as EternalBlue, Drown, or Heartbleed.

Vulnerability Scanning Best Practices 

Now that you know the different types of vulnerability scans and how they help maintain a secure IT infrastructure, let’s look at some of the factors to consider when running these scans. 

Always Scan Everything within the Network 

As a rule of thumb, every device, software, or service within your network should be scanned for any vulnerabilities. You should consider creating an inventory list of all the devices within the network and deciding on which ones to prioritize during the scanning exercise. Remember, every digital asset that touches your ecosystem is a potential threat.

Assign Owners to the Most Critical Assets in the Network 

The risk level of various devices in the network varies. So you want to assign the most vulnerable assets to the most knowledgeable and tech-savvy individuals. This creates accountability while helping boost your other security initiatives, such as patch management system practices.

Document All the Vulnerability Scans

For ease of tracking vulnerability trends and following up with any security commitments, it’s advisable to document all the scans, including their respective results. This also helps streamline the audit process and makes it easy to write reports that the non-technical management personnel can understand.

Prioritize Frequent Scans 

Depending on the size of the organization and the nature of the business, the number of scans you should conduct may vary. For instance, it’s advisable to run at least one scan per month, but a comprehensive vulnerability scan once every quarter will do for smaller businesses with limited resources. 

Keep Your Network Secure Today  

As digital attackers continue to reinvent their techniques, network security is increasingly becoming a cause for concern among businesses of all sizes. One way to keep these bad actors away from your network is to conduct internal and external vulnerability scans to identify threats and fix them early on. 

It’s also advisable to invest in reliable cybersecurity software and tools to help your business stay ahead of new malware and other security risks. If you want to streamline your organization’s vulnerability assessment, you may consider using an automated solution to run internal and external scans, risk mitigation, and compliance management.