From Linux Man Pages
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 format 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 setting 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 communication 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 mes-
sage 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 partition. 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 single or halt.
The disk_error_action should be set to syslog, single, or halt depending on your local policies regarding han-
dling of hardware malfunctions.
FILES
/etc/auditd.conf
Audit daemon configuration file
RELATED
auditd(8)
CATEGORY