What is a component of device hardening?

Patching is a critical component of device hardening as it involves updating software and firmware to fix vulnerabilities that could be exploited by attackers. This process ensures that the system is protected against known security flaws, thus reducing the attack surface of the device. Regular patching helps maintain the integrity and security of devices by addressing weaknesses that could otherwise be exploited.

In contrast, the other choices pertain to different aspects of security and software development. Unit testing is primarily focused on ensuring that individual components of software are functioning as intended, which does not directly relate to hardening the entire device's security. Versioning refers to managing and labeling different versions of software, ensuring compatibility and tracking changes over time, but it does not inherently improve the security posture. Configuring VPN access enhances secure communication over the internet but is not a direct method for hardening the device itself. Thus, patching stands out as the essential activity dedicated specifically to strengthening a device's security.