NAME | DESCRIPTION | NOTES | FILES | SEE ALSO | AUTHOR | COLOPHON

AUDITD.CONF:(5)        System Administration Utilities       AUDITD.CONF:(5)

NAME         top

       auditd.conf - audit daemon configuration file

DESCRIPTION         top

       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 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.

       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.

       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".

NOTES         top

       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.

FILES         top

       /etc/audit/auditd.conf
              Audit daemon configuration file

SEE ALSO         top

       auditd(8), audisp-remote.conf(5).

AUTHOR         top

       Steve Grubb

COLOPHON         top

       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 2017-03-13.
       If you discover any rendering problems in this HTML version of the
       page, or you believe there is a better 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)