auditd.conf

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



NAME
       auditd.conf - audit daemon configuration file

DESCRIPTION
       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.


       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.

       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, 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 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.

       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.

       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/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 loggin 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.

       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


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


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


AUTHOR
       Steve Grubb



Red Hat                            March 2014                    AUDITD.CONF:(5)