Understanding Add-On Security

D.

The Internet Security Glossary (RFC2828) defines add-on security as "The retrofitting of protection mechanisms, implemented by hardware or software, after the [automatic data processing] system has become operational." Source: SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.

Add-on security refers to the additional security measures that are implemented to enhance the security of an information system beyond its built-in or default security features. These measures are typically implemented after the information system has already been put into operation.

Out of the given options, option D is the most accurate definition of add-on security. Protection mechanisms implemented after an information system has become operational can include additional security controls, such as firewalls, intrusion detection and prevention systems, anti-virus and anti-malware software, and data encryption, among others.

Add-on security measures are necessary because no information system can be completely secure against all possible threats and attacks. Cybercriminals are constantly developing new attack methods and techniques to circumvent security controls, and therefore, it is important to regularly review and update the security measures in place to ensure that they are effective.

Add-on security measures are also used to address specific security vulnerabilities that are discovered after an information system has been deployed. For example, if a vulnerability is discovered in the system's software, a patch or update may be released to address the vulnerability and enhance the system's security.

In summary, add-on security is the additional security measures that are implemented after an information system has become operational to enhance its security beyond its built-in or default security features. These measures are necessary to address new and emerging threats and vulnerabilities and ensure that the system remains secure over time.