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AUDITD.CONF:(8) System Administration Utilities AUDITD.CONF:(8)

NAME
auditd.conf - audit daemon configuration file

DESCRIPTION
The file /etc/auditd.conf contains configuration information specific to the audit daemon.
It should contain one configuration keyword per line, an equal sign, and then followed by
appropriate configuration information. The keywords recognized are: log_file, log_format,
flush, freq, num_logs, max_log_file, max_log_file_action, space_left, action_mail_acct,
space_left_action, admin_space_left, admin_space_left_action, disk_full_action, and
disk_error_action. These keywords are described below.

log_file
This keyword specifies the full path name to the log file where audit records will
be stored. It must be a regular file.

log_format
The log format describes how the information should be stored on disk. There are 2
options: raw and nolog. If set to RAW , the audit records will be stored in a for-
mat exactly as the kernel sends it. If this option is set to NOLOG then all audit
information is discarded instead of writing to disk. This mode does not affect data
sent to the audit event dispatcher.

priority_boost
This is a non-negative number that tells the audit damon how much of a priority
boost it should take. The default is 3. No change is 0.

flush Valid values are none, incremental, data, and sync. If set to none, no special
effort is made to flush the audit records to disk. If set to incremental, Then the
freq parameter is used to determine how often an explicit flush to disk is issued.
The data parameter tells the audit damon to keep the data portion of the disk file
sync'd at all times. The sync option tells the audit daemon to keep both the data
and meta-data fully sync'd with every write to disk.

freq This is a non-negative number that tells the audit damon how many records to write
before issuing an explicit flush to disk command. this value is only valid when the
flush keyword is set to incremental.

num_logs
This keyword specifies the number of log files to keep if rotate is given as the
max_log_file_action. If the number is < 2, logs are not rotated. This number must
be 99 or less. The default is 0 - which means no rotation. As you increase the
number of log files being rotated, you may need to adjust the kernel backlog set-
ting upwards since it takes more time to rotate the files. This is typically done
in /etc/audit.rules.

dispatcher
The dispatcher is a program that is started by the audit daemon when it starts up.
It will pass a copy of all audit events to that application's stdin. Make sure you
trust the application that you add to this line since it runs with root privileges.

disp_qos
This option controls whether you want blocking/lossless or non-blocking/lossy com-
munication between the audit daemon and the dispatcher. There is a 128k buffer
between the audit daemon and dispatcher. This is good enogh for most uses. If lossy
is chosen, incoming events going to the dispatcher are discarded when this queue is
full. (Events are still written to disk if log_format is not nolog.) Otherwise the
auditd daemon will wait for the queue to have an empty spot before logging to disk.
The risk is that while the daemon is waiting for network IO, an event is not being
recorded to disk. Valid values are: lossy and lossless. Lossy is the default value.

max_log_file
This keyword specifies the maximum file size in megabytes. When this limit is
reached, it will trigger a configurable action. The value given must be numeric.

max_log_file_action
This parameter tells the system what action to take when the system has detected
that the max file size limit has been reached. Valid values are ignore, syslog,
suspend, rotate and keep_logs. If set to ignore, the audit daemon does nothing.
syslog means that it will issue a warning to syslog. suspend will cause the audit
daemon to stop writing records to the disk. The daemon will still be alive. The
rotate option will cause the audit daemon to rotate the logs. It should be noted
that logs with higher numbers are older than logs with lower numbers. This is the
same convention used by the logrotate utility. The keep_logs option is similar to
rotate except it does not use the num_logs setting. This prevents audit logs from
being overwritten.

action_mail_acct
This option should contain a valid email address or alias. The default address is
root. If the email address is not local to the machine, you must make sure you have
email properly configured on your machine and network. Also, this option requires
that /usr/lib/sendmail exists on the machine.

space_left
This is a numeric value in megabytes that tells the audit daemon when to perform a
configurable action because the system is starting to run low on disk space.

space_left_action
This parameter tells the system what action to take when the system has detected
that it is starting to get low on disk space. Valid values are ignore, syslog,
email, suspend, single, and halt. If set to ignore, the audit daemon does nothing.
syslog means that it will issue a warning to syslog. Email means that it will send
a warning to the email account specified in action_mail_acct as well as sending the
message to syslog. suspend will cause the audit daemon to stop writing records to
the disk. The daemon will still be alive. The single option will cause the audit
daemon to put the computer system in single user mode. halt option will cause the
audit daemon to shutdown the computer system.

admin_space_left
This is a numeric value in megabytes that tells the audit daemon when to perform a
configurable action because the system is running low on disk space. This should be
considered the last chance to do something before running out of disk space. The
numeric value for this parameter should be lower than the number for space_left.

admin_space_left_action
This parameter tells the system what action to take when the system has detected
that it is low on disk space. Valid values are ignore, syslog, email, suspend,
single, and halt. If set to ignore, the audit daemon does nothing. Syslog means
that it will issue a warning to syslog. Email means that it will send a warning to
the email account specified in action_mail_acct as well as sending the message to
syslog. Suspend will cause the audit daemon to stop writing records to the disk.
The daemon will still be alive. The single option will cause the audit daemon to
put the computer system in single user mode. halt

disk_full_action
This parameter tells the system what action to take when the system has detected
that the partition to which log files are written has become full. Valid values are
ignore, syslog, suspend, single, and halt. If set to ignore, the audit daemon does
nothing. Syslog means that it will issue a warning to syslog. Suspend will cause
the audit daemon to stop writing records to the disk. The daemon will still be
alive. The single option will cause the audit daemon to put the computer system in
single user mode. halt option will cause the audit daemon to shutdown the computer
system.

disk_error_action
This parameter tells the system what action to take whenever there is an error
detected when writing audit events to disk or rotating logs. Valid values are
ignore, syslog, suspend, single, and halt. If set to ignore, the audit daemon does
nothing. Syslog means that it will issue a warning to syslog. Suspend will cause
the audit daemon to stop writing records to the disk. The daemon will still be
alive. The single option will cause the audit daemon to put the computer system in
single user mode. halt option will cause the audit daemon to shutdown the computer
system.

NOTES
In a CAPP environment, the audit trail is considered so important that access to system
resources must be denied if an audit trail cannot be created. In this environment, it
would be suggested that /var/log/audit be on its own partition. This is to ensure that
space detection is accurate and that no other process comes along and consumes part of it.

The flush parameter should be set to sync or data.

Max_log_file and num_logs need to be adjusted so that you get complete use of your parti-
tion. It should be noted that the more files that have to be rotated, the longer it takes
to get back to receiving audit events. Max_log_file_action should be set to keep_logs.

Space_left should be set to a number that gives the admin enough time to react to any
alert message and perform some maintenance to free up disk space. This would typically
involve running the aureport -t report and moving the oldest logs to an archive area. The
value of space_left is site dependant since the rate at which events are generated varies
with each deployment. The space_left_action is recommended to be set to email.

Admin_space_left should be set to the amount of disk space on the audit partition needed
for admin actions to be recorded. Admin_space_left_action would be set to single so that
use of the machine is restricted to just the console.

The disk_full_action is triggered when no more room exists on the partition. All access
should be terminated since no more audit capability exists. This can be set to either sin-
gle or halt.

The disk_error_action should be set to syslog, single, or halt depending on your local
policies regarding handling of hardware malfunctions.

FILES
/etc/auditd.conf
Audit daemon configuration file