It is imperative that applications do checks when each function or portion of the application is accessed to ensure that the user is properly authorized. Without continual checks each time a function is accessed, an attacker could forge requests to access portions of the application where authorization has not been granted.
An injection attack is where a malicious actor sends commands or other arbitrary data through input and data fields with the intent of having the application or system execute the code as part of its normal processing and queries. Cross-site scripting occurs when an attacker is able to send untrusted data to a user's browser without going through validation processes. Cross-site request forgery occurs when an attack forces an authenticated user to send forged requests to an application running under their own access and credentials.

The data retention policy covers the duration, format, technologies, protection, and accessibility of archives, but does not address the specific costs of its implementation and maintenance.

Explanation
FIPS 140-2 is a United States certification standard for cryptographic modules, and it provides guidance and requirements for their use based on the requirements of the data classification. However, these are not actual regulatory requirements. The Health Insurance Portability and Accountability Act (HIPAA), Sarbanes-Oxley Act (SOX), and the Payment Card Industry Data Security Standard (PCI DSS) are all major regulatory frameworks either by law or specific to an industry.

The best practice is to totally remove any unneeded services and utilities on a system to prevent any chance of compromise or use. If they are just disabled, it is possible for them to be inadvertently started again at any point, or another exploit could be used to start them again. Removing also negates the need to patch and maintain them going forward.