auditd.conf(images) - phpMan

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 spe-
       cific 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 key-
       words  recognized  are  listed and described below. Each line should be
       limited to 160 characters or the line will be skipped. You may add com-
       ments 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 back-
              log  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  avail-
              able.  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 cho-
              sen, 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  recom-
              mended  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 overwrit-
              ten. 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  config-
              ured  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 sys-
              log.   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 ser-
              vice 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 run-
              ning 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 parame-
              ters 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 exe-
              cute the script. You cannot pass parameters to the script.  Sus-
              pend  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 speci-
              fied, 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 con-
              nections 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 sepa-
              rated 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 AT 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 par-
       tition. 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 depend-
       ing 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 recre-
       ate a connection with the same host addresses and ports until the  con-
       nection 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                           April 2016                   AUDITD.CONF:(5)