Top 10 Open Source Network Security Software in 2025

Network security statistics show that data breaches impacted ~350 million people in the U.S.¹ Open source network security software can prevent unauthorized access to network services and identify the most common cyber attack vectors.

These software continuously monitor a network for malicious activity and take action to prevent it. Read about our feature-based analysis of the top 10 open source network security software:

Top 10 open source network security software

Table 1: Market presence

See open source network security software capabilities for definitions of values in the network security categories column.

Vendor selection criteria:

• Number of GitHub stars: 3,000+
• Updates: At least one update was released in the last week.
• Sorting: Based on GitHub stars in descending order.

1. Metasploit by Rapid7

Metasploit is an open-source framework for creating, testing, and running attack code on remote target computers. It includes a large database of known vulnerabilities and attack modules, allowing security professionals to detect vulnerabilities in a controlled environment. Metasploit’s key features include penetration testing, security research, and vulnerability testing.

Pros

Vulnerability database: Security consultants appreciate the fact that Metasploit contains a large database of vulnerabilities that can be customized to meet the user’s specific needs.

Easy pen testing: Users argue that Metasploit is a valuable tool for any post-exploitation lateral movement. The modules supplied are simple to utilize.

Cons

Long pen testing time: Some reviews show that pen testing time takes long.

Vulnerability reports: Operation managers indicate that the description of the vulnerabilities can be more detailed.

2. Keycloak

Keycloak is an identity and access management software. It has several functionalities: policy management, change management, and user access management. With Keycloak users can:

• Provide role-based access control (RBAC) and more granular and customizable forms of authorization.
• Change network policies to designate who is authorized to connect to the network.  

Read more: NCCM software.

Pros

Identity-based access management: Fintech developers can easily display access levels to each role for multiple positions such as sales, credit manager, and central operations.

Read more: Role-based access control (RBAC), RBAC use cases, RBAC examples.

Application segmentation: Engineers say that they can easily build isolated groups of AWS EKS applications and users.

Read more: Network segmentation tools, microsegmentation tools.

Cons

Policy configurations and monitoring: Some specialists claim that multitenancy configurations and monitoring should be improved.

Read more: Network security policy management solutions.

Community support: Some customers emphasize that the support was not satisfactory.

3. Wazuh

Wazuh is a security platform designed to protect data assets across several environments: on-site, virtualized, containerized, and cloud-based.  Wazuh offers extended detection and response (XDR) and security information and event management (SIEM) features.

Pros

File monitoring: Users say they can effectively evaluate changes in files and detect unauthorized changes on cloud machines.

Malware detection: Users appreciate the platform’s capacity to detect malware at endpoints.

Cons

Network audit logs: Some IT specialists commend that audit logs are not presented on the dashboard.

Integrations and packages: Users claim that integrations are difficult to manage, and some packages have become outdated.

4. Nmap

Nmap is a free network mapper and vulnerability scanner that discovers network nodes and monitors systems for vulnerabilities. The software provides methods to find open ports, detect host devices, see which network services are running, fingerprint operating systems, and identify potential backdoors.

Read more: Network mapping tools,  vulnerability scanning tools. 

Pros

Preventing SYN flooding: Engineers state that SYN flooding attacks employing transmission control protocol TCP can be simply tested using basic Nmap commands.

Configuration options: Users claim that they can specify exactly what they are searching for, such as port ranges, protocols, or IP addresses.

Cons

Learning curve: Some reviewers say that it takes more work to understand how to use the product initially.

Scanning times: IT specialists note that sometimes it takes a long time to execute simple scans.

5. Nikto

Nikto assists in performing security scans on web servers and searching for vulnerabilities in web applications. Nikto is widely used in penetration testing, security assessments, and web application analysis. Nikto is commonly used by developers, pen testers, and security specialists.

Pros

Vulnerability scanning: Users can easily scan for server configuration items such as multiple index files and HTTP server settings.

Pen testing: Users suggest that tools like Nikto provide a solid foundation/framework for testing.

Cons

Lack of graphical user interface (GUI): Users think the tool can be made GUI-based for convenience.

Community support: Reviews show that the user community is not supportive, more development and assistance should be provided.

6. Wireshark by Sullo

Wireshark is an open-source packet sniffer and network security audit tool for detecting and analyzing network traffic. It can troubleshoot network problems, investigate network protocols, and assure network security. Wireshark can study traffic data at several levels.

Pros

Packet inspections: Customers express that it is feasible to analyze packets from several interfaces (LAN, WiFi, Bluetooth, USB).

Read more: Network traffic monitoring.

Detailed communication protocol analysis: Reviews highlight that the solution offers comprehension analysis of communication protocols.

Cons

Graphical customization: Users say that graphical modifications are complex.

Cloud workspace: Saving/sharing works on the cloud is not convenient.

7. Zeek

Zeek started as a research project at the Lawrence Berkeley National Laboratory in 1995. Zeek is widely used for security monitoring. Zeek contributes to security monitoring by investigating network activity. It can detect malicious data streams. based on the data. 

Pros

Network visibility: Consultant notes that Zeek provides high-quality data give comprehensive network traffic visibility, policy enforcement, anomaly detection, and threat-hunting initiatives.

Read more: Insider threat management.

Ease-of-use: Customers note that Zeek is a user-friendly software.

Cons

Community support: Users say that there is no technical support.

Scripting bugs: Some users claim various issues using the scripting language.

8. pfSense by Netgate

pfSense is a firewall and load management system available in the open source pfSense Community Edition and the licensed edition, pfSense Plus (formerly known as pfSense Enterprise). 

The system combines firewall, VPN, and router functions and can be installed either in the cloud (AWS or Azure) or on-premises using a Netgate device.

Pros

Firewall management: Customers say that pfSense offers flexible firewall and router management for L3 firewall and basic routing without vendor lock-in.

Intrusion detection and prevention: Some user expresses that the solution effectively monitors network events and detects intrusion.

Cons

Lack of support: Users say that the lack of REST API support in 2023 is slowing down the installation of new pfSense deployments.

Feature synchronization between software versions: Specialists point out that the divided features between pfSense+ and pfSense CE are an issue because they cannot inspect and audit source code for clients between different software versions.

9. Ossec-hids

OSSEC is a platform for monitoring and controlling your systems. It offers intrusion detection, log monitoring, and security information and event management (SIEM) in an open source solution.

Read more: SIEM use cases.

Pros

Ease-of-use: Users say the product provides effective integrated management and analysis across GUIs.

Intrusion detection: The real-time threat intelligence, reporting, and antivirus management capabilities are appreciated by users.

Cons

Learning curve: Customers convey that the product has a steep learning curve.

Data visualization: Some users argue that there are few choices for data visualization, so they have to rely on email notifications and server log files to investigate network risks.

10.TheHive

TheHive is an open-source incident response platform that enables enterprises to respond to security occurrences and threats. It provides a centralized platform for incident management and monitoring.

Pros

Community support: Security officers note that the platform has an active Discord community where users may share information and ask queries.

Threat intelligence: Customers highlight that TheHive provides robust integration with several threat intelligence systems, such as Cortex and MISP (malware information sharing platform).

Cons

Documentation: Some customers suggest that analyzers and responders might need more documentation.

Integrations: While some users applauded the product integration features some had concerns with Cortex integration, noting that the Cortex integration has slow product updates.

Description of open source network security software categories

1. Penetration testing

A “pen test” is a simulated cyber attack on a computer system, network, or web application. A penetration testing tool is used to detect system vulnerabilities that an attacker could exploit, and assess the efficiency of the system’s security protections.

For example, when pen testers discover vulnerabilities, they use them in simulated assaults that mirror the actions of malicious hackers. This gives security officers a thorough grasp of how hackers might use weaknesses to access sensitive data.

Read more: Penetration testing tools.

2. Identity and access management (IAM) 

Identity and access management (IAM) is a cybersecurity field concerned with how people access digital resources and what they can do with them. IAM systems keep attackers out while guaranteeing that each user only has the permissions they need to complete their duties.

IAM software can simplify access control while allowing legitimate uses to continue. For example, Identity and access management systems provide each user with a unique digital identity that includes rights suited to the user’s role.

3. Unified extended detection and response (XDR) 

Extended detection and response (XDR) is an open cybersecurity architecture combining security tools and unifies security operations at all security layers, including people, endpoints,  networks, cloud workloads, and data.

Security solutions from XDR might incorporate:

• Software that is tailored to manage user activities: Firewalls, antivirus software, and user and entity behavior analytics (UEBA);

• Software tailored to a particular layer: Network traffic analysis tools, endpoint protection platforms (EPPs), and endpoint detection & response, EDR tools;

• Software that collects data or manages workflows across security layers: Security orchestration, automation, and response (SOAR) and security information and event management (SIEM) are two examples of solutions that gather data or manage workflows across security layers. 

Read more: SIEM use cases.

4. Vulnerability scanning

Vulnerability scanning, often known as “vulnerability assessment,” is assessing networks or IT assets for security faults or holes that external or internal threat actors may exploit.  For example, vulnerability scanners seek for bugs in an operating system’s remote desktop protocol.

Read more: Network mapping tools,  vulnerability scanning tools. 

5. Packet sniffing

A packet sniffer (a.k.a. a packet analyzer, policy analyzer, or network analyzer) is a hardware or software that monitors network traffic. Sniffers examine streams of data packets that move between networked computers and the Internet.

6. Network security audit

A network security audit technologies monitor and analyze network infrastructure and systems accessible via the Internet. It also entails examining network policies employed and network devices.

Read more: Network security audit tools.

7. Network security monitoring (NSM)

Network security monitoring (NSM) gathers and analyzes data to detect or react to security risks on a network. This procedure entails employing monitoring software and other technologies to obtain insight into traffic flow.

Read more: Network security monitoring tools

8. Security information and event management (SIEM)

SIEM technologies gather, correlate, and analyze data from multiple sources, including logs, security alerts, and events, and store it in a centralized platform for real-time security monitoring.

9. Intrusion detection and response

An intrusion detection and response tool is a network safety system that scans network traffic for malicious behavior.

Read more: IPS tools.

What to look for when selecting an open source network security tool

1. Evaluate the software’s reputation: The number of GitHub stars and contributors demonstrates the popularity of open source network security technology. Tools with higher GitHub stars and contributors will receive benefits such as:

• Stronger community support
  
  • Larger user base: Tools with high GitHub stars typically have a large and active user community, which means more people to ask for help, share knowledge, and discuss best practices.
  • More frequent updates: High contributor counts often lead to more frequent updates and improvements, ensuring the tool stays up-to-date with the latest technologies and standards.
    
• Better quality and reliability
  
  • Higher performance: More contributors can improve code quality and robustness as multiple perspectives and expertise are applied to solve problems and improve the code.
  • More bug fixes: Issues and bugs are more likely to be identified and fixed quickly due to the high level of community involvement.

• Comprehensive documentation: Popular tools often have extensive documentation, tutorials, and guides created by the software community, making it easier for new users to get started and for experienced users to find advanced usage tips.

2. Analyze the software’s features: Most open source network security solutions include firewall assessment, data breach incident response, and intrusion prevention capabilities. However, if your company intends to use the network security tool for multiple applications, look for a more comprehensive solution. For example, a company looking for identity-based access controls may choose a system with role-based access control (RBAC) features.
   
3. Compare open-source and closed-source alternatives: While open-source solutions frequently have limited integrations, less specialized features, and no professional support using a more tailored solution with:
   -more comprehensive features (for example, data security posture management),
   -detailed official documentation,
   -a dedicated team to quickly patch security vulnerabilities.

can be more effective for your company.

Here’s a list of closed-source network security software that provides data security posture management (DSPM), microsegmentation, network audit, network security monitoring, network security policy management (NSPM), and software-defined perimeter (SDP)  capabilities. 

Other important network security software to build a strong cybersecurity posture

Microsegmentation tools: Separate a network into granular segments and implement security controls based on the needs of each segment.

DSPM vendors: Provide network visibility into where to find sensitive data, who has access to it, and how it has been used across the cloud.

SDP software: Deliver a software-defined perimeter (SDP) across the cloud to determine who gets access to what resources.

Network traffic analyzers (NTA): Collects and analyzes network flow data to give insight into traffic volume and type and network device performance.

Network performance monitoring tools: Monitor and evaluate network performance to discover and rectify issues that may have an impact on the network’s overall performance including excessive latency, lost connections, and low performance.

Further reading

• Role-based Access Control (RBAC)  
• Network Segmentation: 6 Benefits & 8 Best Practices
• 80+ Network Security Statistics

External Links

• 1. ITRC 2023 Annual Data Breach Report - ITRC. Identity Theft Resource Center