Provided by: auditd_2.8.5-2ubuntu1_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  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.  You
              may  also  append  a  percent sign (e.g. 5%) to the number to have the audit daemon
              calculate the number based on the disk partition size.

       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.
              You may also append a percent sign (e.g. 1%) to the number to have the audit daemon
              calculate the number based on the disk partition size.

       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