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NAME | DESCRIPTION | NOTES | FILES | SEE ALSO | AUTHOR | COLOPHON |
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AUDITD.CONF:(5) System Administration Utilities AUDITD.CONF:(5)
auditd.conf - audit daemon configuration file
The file /etc/audit/auditd.conf contains configuration information
specific to the audit daemon. Each line should contain one
configuration keyword, an equal sign, and then followed by
appropriate configuration information. All option names and values
are case insensitive. The keywords recognized are listed and
described below. Each line should be limited to 160 characters or the
line will be skipped. You may add comments to the file by starting
the line with a '#' character.
local_events
This yes/no keyword specifies whether or not to include local
events. Normally you want local events so the default value is
yes. Cases where you would set this to no is when you want to
aggregate events only from the network. At the moment, this is
useful if the audit daemon is running in a container. This
option can only be set once at daemon start up. Reloading the
config file has no effect.
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.
write_logs
This yes/no keyword determines whether or not to write logs to
the disk. Normally you want this so the default is yes.
log_format
The log format describes how the information should be stored
on disk. There are 2 options: raw and enriched. If set to RAW,
the audit records will be stored in a format exactly as the
kernel sends it. The ENRICHED option will resolve all uid,
gid, syscall, architecture, and socket address information
before writing the event to disk. This aids in making sense of
events created on one system but reported/analized on another
system. The NOLOG option is now deprecated. If you were
setting this format, now you should set the write_logs option
to no.
log_group
This keyword specifies the group that is applied to the log
file's permissions. The default is root. The group name can be
either numeric or spelled out.
priority_boost
This is a non-negative number that tells the audit daemon how
much of a priority boost it should take. The default is 4. No
change is 0.
flush Valid values are none, incremental, incremental_async, 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 incremental_async parameter is
very much like incremental except the flushing is done
asynchronously for higher performance. The data parameter
tells the audit daemon 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. The default value is incremental_async.
freq This is a non-negative number that tells the audit daemon 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 or incremental_async.
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 999 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/audit.rules. If log rotation is configured to
occur, the daemon will check for excess logs and remove them
in effort to keep disk space available. The excess log check
is only done on startup and when a reconfigure results in a
space check.
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 enough 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.
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.
name_format
This option controls how computer node names are inserted into
the audit event stream. It has the following choices: none,
hostname, fqd, numeric, and user. None means that no computer
name is inserted into the audit event. hostname is the name
returned by the gethostname syscall. The fqd means that it
takes the hostname and resolves it with dns for a fully
qualified domain name of that machine. Numeric is similar to
fqd except it resolves the IP address of the machine. In order
to use this option, you might want to test that 'hostname -i'
or 'domainname -i' returns a numeric address. Also, this
option is not recommended if dhcp is used because you could
have different addresses over time for the same machine. User
is an admin defined string from the name option. The default
value is none.
name This is the admin defined string that identifies the machine
if user is given as the name_format option.
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. The effect is that logs accumulate and
are not deleted - which will trigger the space_left_action if
the volume fills up. This is best used in combination with an
external script used to archive logs on a periodic basis.
verify_email
This option determines if the email address given in
action_mail_acct is checked to see if the domain name can be
resolved. This option must be given before action_mail_acct or
the default value of yes will be used.
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, rotate, email, exec,
suspend, single, and halt. If set to ignore, the audit daemon
does nothing. syslog means that it will issue a warning to
syslog. rotate will rotate logs, losing the oldest to free up
space. 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. exec /path-to-script will execute the
script. You cannot pass parameters to the script. The script
is also responsible for telling the auditd daemon to resume
logging once its completed its action. This can be done by
adding service auditd resume to the script. 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. The 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, rotate, email, exec, suspend,
single, and halt. If set to ignore, the audit daemon does
nothing. Syslog means that it will issue a warning to syslog.
rotate will rotate logs, losing the oldest to free up space.
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. exec /path-to-script will execute the script. You
cannot pass parameters to the script. The script is also
responsible for telling the auditd daemon to resume logging
once its completed its action. This can be done by adding
service auditd resume to the script. 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. The
halt option will cause the audit daemon to shutdown the
computer system.
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,
rotate, exec, suspend, single, and halt. If set to ignore,
the audit daemon will issue a syslog message but no other
action is taken. Syslog means that it will issue a warning to
syslog. rotate will rotate logs, losing the oldest to free up
space. exec /path-to-script will execute the script. You
cannot pass parameters to the script. The script is also
responsible for telling the auditd daemon to resume logging g
once its completed its action. This can be done by adding
service auditd resume to the script. 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, exec,
suspend, single, and halt. If set to ignore, the audit daemon
will not take any action. Syslog means that it will issue no
more than 5 consecutive warnings to syslog. exec /path-to-
script will execute the script. You cannot pass parameters to
the script. 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.
tcp_listen_port
This is a numeric value in the range 1..65535 which, if
specified, causes auditd to listen on the corresponding TCP
port for audit records from remote systems. The audit daemon
may be linked with tcp_wrappers. You may want to control
access with an entry in the hosts.allow and deny files. If
this is deployed on a systemd based OS, then you may need to
adjust the 'After' directive. See the note in the
auditd.service file.
tcp_listen_queue
This is a numeric value which indicates how many pending
(requested but unaccepted) connections are allowed. The
default is 5. Setting this too small may cause connections to
be rejected if too many hosts start up at exactly the same
time, such as after a power failure.
tcp_max_per_addr
This is a numeric value which indicates how many concurrent
connections from one IP address is allowed. The default is 1
and the maximum is 1024. Setting this too large may allow for
a Denial of Service attack on the logging server. Also note
that the kernel has an internal maximum that will eventually
prevent this even if auditd allows it by config. The default
should be adequate in most cases unless a custom written
recovery script runs to forward unsent events. In this case
you would increase the number only large enough to let it in
too.
use_libwrap
This setting determines whether or not to use tcp_wrappers to
discern connection attempts that are from allowed machines.
Legal values are either yes, or no The default value is yes.
tcp_client_ports
This parameter may be a single numeric value or two values
separated by a dash (no spaces allowed). It indicates which
client ports are allowed for incoming connections. If not
specified, any port is allowed. Allowed values are 1..65535.
For example, to require the client use a priviledged port,
specify 1-1023 for this parameter. You will also need to set
the local_port option in the audisp-remote.conf file. Making
sure that clients send from a privileged port is a security
feature to prevent log injection attacks by untrusted users.
tcp_client_max_idle
This parameter indicates the number of seconds that a client
may be idle (i.e. no data from them at all) before auditd
complains. This is used to close inactive connections if the
client machine has a problem where it cannot shutdown the
connection cleanly. Note that this is a global setting, and
must be higher than any individual client heartbeat_timeout
setting, preferably by a factor of two. The default is zero,
which disables this check.
enable_krb5
If set to "yes", Kerberos 5 will be used for authentication
and encryption. The default is "no".
krb5_principal
This is the principal for this server. The default is
"auditd". Given this default, the server will look for a key
named like auditd/hostname@EXAMPLE.COM stored in
/etc/audit/audit.key to authenticate itself, where hostname is
the canonical name for the server's host, as returned by a DNS
lookup of its IP address.
krb5_key_file
Location of the key for this client's principal. Note that
the key file must be owned by root and mode 0400. The default
is /etc/audit/audit.key
distribute_network
If set to "yes", network originating events will be
distributed to the audit dispatcher for processing. The
default is "no".
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 dependent since the rate at which events are
generated varies with each deployment. The space_left_action is
recommended to be set to email. If you need something like an snmp
trap, you can use the exec option to send one.
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 handling of hardware
malfunctions.
Specifying a single allowed client port may make it difficult for the
client to restart their audit subsystem, as it will be unable to
recreate a connection with the same host addresses and ports until
the connection closure TIME_WAIT state times out.
/etc/audit/auditd.conf
Audit daemon configuration file
auditd(8), audisp-remote.conf(5).
Steve Grubb
This page is part of the audit (Linux Audit) project. Information
about the project can be found at
⟨http://people.redhat.com/sgrubb/audit/⟩. If you have a bug report
for this manual page, send it to linux-audit@redhat.com. This page
was obtained from the project's upstream Git repository
⟨https://github.com/linux-audit/audit-userspace.git⟩ on 2018-02-02.
(At that time, the date of the most recent commit that was found in
the repository was 2018-01-23.) If you discover any rendering prob‐
lems in this HTML version of the page, or you believe there is a bet‐
ter or more up-to-date source for the page, or you have corrections
or improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to man-pages@man7.org
Red Hat April 2016 AUDITD.CONF:(5)
Pages that refer to this page: auditd(8)
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