Copyright (c) 2017 Peter Tribble
Copyright (c) 2008, Sun Microsystems, Inc. All Rights Reserved
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/usr/lib/security/audit_syslog.so
The audit_syslog plugin module for audit, /usr/lib/security/audit_syslog.so, provides realtime conversion of audit data to syslog-formatted (text) data and sends it to a syslog daemon as configured in syslog.conf(5).
Messages to syslog are written if the audit_syslog plugin is activated and configured using auditconfig(8).
Syslog messages are generated with the facility code of LOG_AUDIT (audit in syslog.conf(5)) and severity of LOG_NOTICE. Audit syslog messages contain data selected from the tokens described for the binary audit log. (See audit.log(5)). As with all syslog messages, each line in a syslog file consists of two parts, a syslog header and a message.
The syslog header contains the date and time the message was generated, the host name from which it was sent, auditd to indicate that it was generated by the audit daemon, an ID field used internally by syslogd, and audit.notice indicating the syslog facility and severity values. The syslog header ends with the characters ], that is, a closing square bracket and a space.
The message part starts with the event type from the header token. All subsequent data appears only if contained in the original audit record and there is room in the 1024-byte maximum length syslog line. In the following example, the backslash (\e) indicates a continuation; actual syslog messages are contained on one line:
Oct 31 11:38:08 smothers auditd: [ID 917521 audit.notice] chdir(2) ok\e session 401 by joeuser as root:other from myultra obj /export/home
In the preceding example, chdir(2) is the event type. Following this field is additional data, described below. This data is omitted if it is not contained in the source audit record. ok or failed
Comes from the return or exit token.
<#> is the session ID from the subject token.
<name> is the audit ID from the subject token.
<name> is the effective user ID and <group> is the effective group ID from the subject token.
The zone name. This field is generated only if the zonename audit policy is set.
<terminal> is the text machine address from the subject token.
<path> is the path from the path token The path can be truncated from the left if necessary to fit it on the line. Truncation is indicated by leading ellipsis (...).
<owner> is the effective user ID of the process owner.
<owner> is the audit ID of the process owner.
The following are example syslog messages:
Nov 4 8:27:07 smothers auditd: [ID 175219 audit.notice] \e system booted Nov 4 9:28:17 smothers auditd: [ID 752191 audit.notice] \e login - rlogin ok session 401 by joeuser as joeuser:staff from myultra Nov 4 10:29:27 smothers auditd: [ID 521917 audit.notice] \e access(2) ok session 255 by janeuser as janeuser:staff from \e 129.146.89.30 obj /etc/passwd
The p_flags attribute is used to further filter audit data being sent to the syslog daemon beyond the default and non-attributable audit flags. The parameter is a comma-separated list; each item represents an audit class (see audit_class(5)) and is specified using the same syntax used by auditconfig for the -setflags and -setnaflags options. The default (no p_flags set) is that no audit records are generated.
Example 1 Enabling the plugin and selecting events
The command below enables the audit_syslog plugin and sets the p_flags filter to allow class records for lo but allows class records for am for failures only. Because no other classes are listed, not other audit records will be sent to syslog. You cannot add classes to those defined by means of flags and naflags. You can only remove them.
# autditconf -setplugin audit_syslog active p_flags=lo,-amExample 2 Viewing the plugin configuration
The command below enables shows the audit_syslog plugin configuration.
# auditconfig -getplugin audit_syslog Plugin: audit_syslog (active) Attributes: p_flags=lo,-am;
See attributes(7) for a description of the following attributes:
| ATTRIBUTE TYPE ATTRIBUTE VALUE |
| MT Level MT-Safe |
| Interface Stability See below. |
The message format and message content are Uncommitted. The configuration parameters are Committed.
audit_class (5), syslog.conf (5), attributes (7), auditconfig (8), auditd (8)
Use of the plugin configuration line to include audit_syslog.so requires that /etc/syslog.conf is configured to store syslog messages of facility audit and severity notice or above in a file intended for audit records. An example of such a line in syslog.conf is:
audit.notice /var/audit/audit.log
Messages from syslog are sent to remote syslog servers by means of UDP, which does not guarantee delivery or ensure the correct order of arrival of messages.
If the p_flags attribute results in no classes being preselected, an error is reported by means of a syslog alert with the LOG_DAEMON facility code.
The time field in the syslog header is generated by syslog(3C) and only approximates the time given in the binary audit log. Normally the time field shows the same whole second or at most a few seconds difference.