An incident response plan (IRP) is a document that defines the roles and responsibilities, procedures, and guidelines for responding to a security incident. It helps the security team to act quickly and effectively, minimizing the impact and cost of the incident. An IRP should specify who should conduct the next steps following a security event, such as containment, eradication, recovery, and analysis12. References: CompTIA CySA+ CS0-003 Certification Study Guide, page 362; 6 Incident Response Steps to Take After a Security Event, section 2.

The next step in the remediation process after applying a software patch is validation. Validation is a process that involves verifying that the patch has been successfully applied, that it has fixed the vulnerability, and that it has not caused any adverse effects on the system or application functionality or performance. Validation can be done using various methods, such as scanning, testing, monitoring, or auditing.

MITRE ATT&CK is a globally accessible knowledge base of adversary tactics and techniques based on real- world observations. It is used as a foundation for the development of specific threat models and methodologies in the private sector, in government, and in the cybersecurity product and service community.
It can help security professionals understand, detect, and mitigate cyber threats by providing a comprehensive framework of TTPs.
References: MITRE ATT&CK, Getting Started with ATT&CK, MITRE ATT&CK | MITRE