Considerations When Planning What to Audit

What is audited at your site is based on your site policy and the costs of auditing (time, efficiency, disk space). For a discussion of the costs, see "Controlling Audit Costs ". The following are factors to consider when using auditing as it is implemented in the Trusted Solaris environment.

• Every audit record stands alone, so records can quickly fill up disk space.

  Therefore, you might want to start with a small amount of auditing and see how the audit partitions fill. You can then make more educated estimates of disk requirements and an audit archiving schedule. You can refine audit classes as you get an estimate of the size of the audit trail.

• The number of events in an audit class does not necessarily correlate to how many records are generated.

  For example, the file read class contains about the same number of events as the login or logout class. Enabling the file read class for success is likely to generate many more records than enabling the login or logout class for success.

• Auditing for failure locates abnormal events; auditing for success monitors system use.

  If site policy requires monitoring of system use, you will want to set aside more space for the audit trail than if you are auditing for abnormal events.

• Auditing for failure may generate many fewer records than auditing for success.

  For example, auditing for failure of file read events in a Trusted Solaris system of sophisticated users can generate many fewer records than turning on the file read class for success.

• Configuring the audit classes differently, or setting up new audit classes for audit events can more efficiently satisfy your site requirements. By excluding audit events that site policy does not require to be audited, the audit trail is smaller.

  For example, you may want to create a class de for devices. When configuring devices, audit the class for success to generate a record of what devices have been set up and tested. When all devices have been configured, you may want to audit the class for failure.

• Configuring some classes to be audited intermittently may satisfy your site requirements.

  For example, you may want to audit the audit class you created, de, intermittently. A cron job, or the command auditconfig(1M), enable you to turn auditing on and off for particular classes and set other audit flags dynamically.