Which of the following is an example of an open-source security tool?

Wireshark is an example of an open-source security tool because it is developed and distributed under an open-source license, allowing users to view, modify, and distribute the source code. This transparency is a key characteristic of open-source software, enabling the community to contribute to its improvement and security. Wireshark is widely used for network protocol analysis, providing insights into network traffic, troubleshooting issues, and detecting anomalies.

On the other hand, the other options represent commercial security tools that are proprietary software. They are developed and maintained by their respective companies and do not provide public access to their source code. This distinction is essential in understanding the differences between open-source and proprietary software, particularly in the context of security tools.