Provided by: auditd_2.8.2-1ubuntu1_amd64 bug

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.

       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.

       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".

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