audit system parameters
The audit(4) subsystem has
been deprecated since macOS 11.0, disabled since macOS 14.0, and WILL BE
REMOVED in a future version of macOS. Applications that require a
security event stream should use the
On this version of macOS, you can re-enable
audit(4) by renaming or copying
/etc/security/audit_control, re-enabling the
system/com.apple.auditd service by running
launchctl enable system/com.apple.auditd as root, and rebooting.
audit_control file contains several
audit system parameters. Each line of this file is of the form:
The parameters are:
- The directory where audit log files are stored. There may be more than one
of these entries. Changes to this entry can only be enacted by restarting
the audit system. See audit(8) for a
description of how to restart the audit system.
- Specifies which audit event classes are audited for all users.
audit_user(5) describes how to
audit events for individual users. See the information below for the
format of the audit flags.
- Specify the hostname or IP address to be used when setting the local
systems's audit host information. This hostname will be converted into an
IP or IPv6 address and will be included in the header of each audit
record. Due to the possibility of transient errors coupled with the
security issues in the DNS protocol itself, the use of DNS should be
avoided. Instead, it is strongly recommended that the hostname be
specified in the /etc/hosts file. For more information see
- Contains the audit flags that define what classes of events are audited
when an action cannot be attributed to a specific user.
- The minimum free space required on the file system audit logs are being
written to. When the free space falls below this limit a warning will be
issued. If no value for the minimum free space is set, the default of 20
percent is applied by the kernel.
- A list of global audit policy flags specifying various behaviors, such as
fail stop, auditing of paths and arguments, etc.
- Maximum trail size in bytes; if set to a non-0 value, the audit daemon
will rotate the audit trail file at around this size. Sizes less than the
minimum trail size (default of 512K) will be rejected as invalid. If 0,
trail files will not be automatically rotated based on file size. For
convenience, the trail size may be expressed with suffix letters: B
(Bytes), K (Kilobytes), M (Megabytes), or G (Gigabytes). For example, 2M
is the same as 2097152.
- Specifies when audit log files will expire and be removed. This may be
after a time period has passed since the file was last written to or when
the aggregate of all the trail files have reached a specified size or a
combination of both. If no expire-after parameter is given then audit log
files will not expire and be removed by the audit control system. See the
information below for the format of the expiration specification.
Audit flags are a comma-delimited list of audit classes as defined
in the audit_class(5) file. Event
classes may be preceded by a prefix which changes their interpretation. The
following prefixes may be used for each class:
- Record both successful and failed events.
- Record successful events.
- Record failed events.
- Record neither successful nor failed events.
- Do not record successful events.
- Do not record failed events.
The policy flags field is a comma-delimited list of policy flags
from the following list:
- Allow processes to continue running even though events are not being
audited. If not set, processes will be suspended when the audit store
space is exhausted. Currently, this is not a recoverable state.
- Fail stop the system if unable to audit an event—this consists of
first draining pending records to disk, and then halting the operating
- Audit command line arguments to
- Audit environmental variable arguments to
- Include a unique audit sequence number token in generated audit records
(not implemented on FreeBSD or Darwin).
- Include supplementary groups list in generated audit records (not
implemented on FreeBSD or Darwin; supplementary
groups are never included in records on these systems).
- Append a trailer token to each audit record (not implemented on
FreeBSD or Darwin; trailers are always included in
records on these systems).
- Include secondary file paths in audit records (not implemented on
FreeBSD or Darwin; secondary paths are never
included in records on these systems).
- Include a zone ID token with each audit record (not implemented on
FreeBSD or Darwin; FreeBSD
audit records do not currently include the jail ID or name).
- Enable auditing for each local zone (not implemented on
FreeBSD or Darwin; on
FreeBSD, audit records are collected from all
jails and placed in a single global trail, and only limited audit controls
are permitted within a jail).
It is recommended that installations set the
cnt flag but not
unless it is intended that audit logs exceeding available disk space halt
The expiration specification can be one value or two values with
the logical conjunction of AND/OR between them. Values for the audit log
file age are numbers with the following suffixes:
- Log file age in seconds.
- Log file age in hours.
- Log file age in days.
- Log file age in years.
Values for the disk space used are numbers with the following
- (space) or
- Disk space used in Bytes.
- Disk space used in Kilobytes.
- Disk space used in Megabytes.
- Disk space used in Gigabytes.
The suffixes on the values are case sensitive. If both an age and
disk space value are used they are seperated by AND or OR and both values
are used to determine when audit log files expire. In the case of AND, both
the age and disk space conditions must be met before the log file is
removed. In the case of OR, either condition may expire the log file. For
will expire files that are older than 60 days but only if 1
gigabyte of disk space total is being used by the audit logs.
The following settings appear in the default
The flags parameter above specifies the
system-wide mask corresponding to login/logout as well as authentication and
authorization events. The policy parameter specifies
that the system should neither fail stop nor suspend processes when the
audit store fills and that command line arguments should be audited for
AUE_EXECVE events. The trail file will be
automatically rotated by the audit daemon when the file size reaches
approximately 2MB. Trail files will expire when their aggregate size exceeds
The OpenBSM implementation was created by McAfee Research, the
security division of McAfee Inc., under contract to Apple Computer Inc. in
2004. It was subsequently adopted by the TrustedBSD Project as the
foundation for the OpenBSM distribution.
This software was created by McAfee Research, the security
research division of McAfee, Inc., under contract to Apple Computer Inc.
Additional authors include Wayne Salamon,
Robert Watson, and SPARTA Inc.
The Basic Security Module (BSM) interface to audit records and
audit event stream format were defined by Sun Microsystems.