Potentially adverse events are analyzed

All security incidents are addressed in a consistent manner to improve security based on what has happened.

In the incident treatment process:

• the reported incident is confirmed (or found unnecessary to record)
• the type and cause of incident is documented
• the risks associated with the incident are documented
• the risks are re-evaluated and treated if that is necessary after the incident
• risk mitigation measures or a decision their acceptance is documented
• people who need to be informed of the results of the incident treatment are identified (including external ones)
• possible need for a post-incident analysis is determined

The organization must be aware of the logs that accrue from the use of different data systems, whether generating the logs is the responsibility of the organization or the system provider. Logs record user actions as well as anomalies, errors, and security incidents.

The adequacy of log should be reviewed regularly. If necessary, log should be usable to determine the root causes for system incidents.

System logs often contain a wealth of information, much of which is irrelevant to security monitoring. In order to identify events relevant to security monitoring, consideration should be given to automatically copying appropriate message types to another log or to using appropriate utilities or audit tools to review and resolve files.

The organization shall define procedures for clearly sorting detected security events. Sorting must enable the prioritizing of events according to severity and potential impact.

Sorting is intended to enhance the investigation and evaluation of security events so that, for example, a response to a disruption can be initiated quickly.

Procedures can consist of common processes, technical tools, or algorithms that utilize machine learning. Procedures need to be reviewed regularly to ensure that they work and are appropriate for their needs.

After a disturbance, a forensic examination must be carried out on the malicious code or other remnants of the disturbance. A safe investigation in a closed environment can open up the causes, goals, and motives of the incident. This helps the organization fix potential security vulnerabilities, prepare for similar incidents, and identify or profile a potential attacker.