How to Merge Audit Records

This task shows you how to merge all audit files in all the audit directories. Follow these steps when you want to analyze the contents of the audit trail.

1. Become superuser or assume an equivalent role.

2. Change directories to the primary audit directory.

   # cd /etc/security/audit/server-name.1/files

   The merged file is placed in the /etc/security/audit/server-name.1/files directory. This directory is a protected directory.

3. Merge the audit records.

   # auditreduce > merged.log

   All directories that are listed in the dir: lines of the audit_control file on server-name are merged. The merged records are then placed in the merged.log file in the current directory.

Example—Displaying the Entire Audit Trail

To display the entire audit trail at once, pipe the output of the auditreduce command into the praudit command.

# auditreduce | praudit

Example—Printing the Entire Audit Trail

With a pipe to the lp command, the output goes to the printer.

# auditreduce | praudit | lp

Example—Combining and Reducing Audit Files

Use the auditreduce command with the -O option to combine several audit files into one file and to save the files in a specified output file. auditreduce can do this type of combination and deletion automatically. See the -C and -D options in the auditreduce(1M) man page. However, you can select the files manually to good effect. Use the find command, then use auditreduce to combine just the named set of files.

When used in this way, the auditreduce command merges all the records from its input files into a single output file. The input files should then be deleted. In addition, the output file should be kept in a directory that is named /etc/security/audit/server-name/files so that auditreduce can find the output file.

# auditreduce -O combined-filename

The auditreduce command can also reduce the number of records in its output file. The command can eliminate the less interesting records as it combines the input files. For example, you might use the auditreduce command to retain only the login and logout records in audit files that are over a month old. If you need to retrieve the complete audit trail, you could recover the trail from backup tapes.

# auditreduce -O daily.summary -b 19990413 -c lo; compress *daily.summary
# mv *daily.summary /etc/security/summary.dir

Example—Displaying User Activity From a Selected Date

In the following example, the system administrator checks to see when user tamiko logged in and logged out on April 13, 1999. The administrator requests the lo event class. The short-form date is in the form yymmdd. The long form is described in the auditreduce(1M) man page.

# auditreduce -d 990413 -u tamiko -c lo | praudit

Example—Copying Selected Records to a Single File

In this example, login and logout messages for a particular day are selected from the audit trail. The messages are merged into a target file. The target file is written in a directory other than the normal audit root directory.

# auditreduce -c lo -d 990413 -O /usr/audit_summary/logins 

The -O option creates an audit file with 14-character timestamps for both the start-time and the end-time, with the suffix logins:

/usr/audit_summary/19990413000000.19990413235959.logins

Example—Cleaning Up a not_terminated Audit File

Occasionally, an audit daemon dies while its audit file is still open. Or, a server becomes inaccessible and forces the machine to switch to a new server. In such instances, an audit file remains with the string not_terminated as the end-time, even though the file is no longer used for audit records. When you find such a file, you can manually verify that the file is no longer in use. You can clean up the open file by specifying the name of the file with the correct options.

# audit -s
19990414121112.not_terminated.egret
# auditreduce -O egret 19990413120429.not_terminated.egret

The audit command checks the name of the current audit file. The auditreduce command creates a new audit file with the correct name and correct timestamps. The correct name includes the correct suffix (egret). The auditreduce then copies all the records into the file.