Description: A hardened image is a virtual machine image that has been secured by removing unnecessary services and applications. This hardening process aims to reduce the attack surface of the virtual machine, thereby minimizing vulnerabilities that could be exploited by attackers. Hardened images are essential in cloud and virtualization environments, where security is a priority. By eliminating non-essential components, security is enhanced, and performance is improved as resource load is reduced. Additionally, these images often include predefined security configurations, such as firewall policies and access settings, which further reinforce system protection. In the context of ‘Configuration as Code’, hardened images allow DevOps and security teams to implement and manage environments more efficiently and securely, ensuring that each instance of the virtual machine meets established security standards from the outset.
History: The concept of hardened images began to gain relevance in the late 1990s and early 2000s, in a context where virtualization and cloud computing were starting to gain traction. With the rise of cyber threats, organizations began seeking ways to secure their virtual environments. In 2005, the Defense Information Systems Agency (DISA) introduced the ‘Security Technical Implementation Guide’ (STIG), which provided guidelines for hardening operating systems and applications. Since then, image hardening has become a standard practice in the cybersecurity industry.
Uses: Hardened images are primarily used in cloud and virtualization environments to ensure that virtual machine instances are secure from the outset. They are applied in the creation of web servers, databases, and critical applications where security is paramount. Additionally, they are useful in security audits and regulatory compliance, as they allow organizations to demonstrate that they have taken proactive measures to protect their systems.
Examples: An example of a hardened image is a web server image that has been configured to run only the necessary services, such as HTTP and HTTPS, while disabling other services that are not required. Another case is the use of hardened images in container environments, where container images are created that only include the libraries and tools necessary to run a specific application, thereby minimizing vulnerabilities.
