Auditing is the collection of data that provides a record of security-related system events. This data can then be used to assign responsibility to actions that take place on a host. Successful auditing starts with two security features: identification and authentication. At login, after a user supplies a user name and password, a unique audit ID is associated with the user's process. The audit ID is inherited by every process that is started during the login session. Even if a user changes identity (see the su(1M) man page), all user actions are tracked with the same audit ID.
Auditing makes it possible to do the following:
Monitor security-relevant events that take place on the host
Record the events in a network-wide audit trail
Detect misuse or unauthorized activity
Review patterns of access, and see the access histories of individuals and objects
Discover attempts to bypass the protection mechanisms
Discover extended use of privilege that occurs when a user changes identity
During system configuration, you select which activities to monitor. You can also fine-tune the degree of auditing that is done for individual users.
After audit data is collected, audit-reduction and interpretation tools allow you to examine interesting parts of the audit trail. For example, you can choose to review audit records for individual users or groups, to examine all records for a certain type of event on a specific day, or to select records that were generated at a certain time of day.