The Linux Audit Parser can parse the log messages of the Linux Audit subsystem (auditd). The syslog-ng OSE application can separate these log messages to name-value pairs. For details on using value-pairs in syslog-ng OSE see Structuring macros, metadata, and other value-pairs. The following is a sample log message of auditd:
type=SYSCALL msg=audit(1441988805.991:239): arch=c000003e syscall=59 success=yes exit=0 a0=7fe49a6d0e98 a1=7fe49a6d0e40 a2=7fe49a6d0e80 a3=2 items=2 ppid=3652 pid=3660 auid=1000 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=5 comm="dumpe2fs" exe="/sbin/dumpe2fs" key=(null) type=EXECVE msg=audit(1441988805.991:239): argc=3 a0="dumpe2fs" a1="-h" a2="/dev/sda1" type=CWD msg=audit(1441988805.991:239): cwd="/" type=PATH msg=audit(1441988805.991:239): item=0 name="/sbin/dumpe2fs" inode=137078 dev=08:01 mode=0100755 ouid=0 ogid=0 rdev=00:00 nametype=NORMAL type=PATH msg=audit(1441988805.991:239): item=1 name="/lib64/ld-linux-x86-64.so.2" inode=5243184 dev=08:01 mode=0100755 ouid=0 ogid=0 rdev=00:00 nametype=NORMAL type=PROCTITLE msg=audit(1441988805.991:239): proctitle=64756D7065326673002D68002F6465762F73646131
Certain fields of the audit log can be encoded in hexadecimal format, for example, the arch field, or the a<number> fields in the previous example. The &abbrev; application automatically decodes these fields (for example, the c000003e value becomes x86_64).
The syslog-ng OSE application extracts every field into name-value pairs. It automatically decodes the following fields:
name
proctitle
path
dir
comm
ocomm
data
old
new
To parse the log messages of the Linux Audit subsystem, define a parser that has the linux-audit-parser() option. By default, the parser will process the ${MESSAGE} part of the log message. To process other parts of a log message, use the template() option. You can also define the parser inline in the log path.
parser parser_name { linux-audit-parser( prefix() template() ); };
In the following example, the source is a log file created by auditd. Since the audit log format is not a syslog format, the syslog parser is disabled, so that syslog-ng OSE does not parse the message: flags(no-parse). The parser inserts ".auditd." prefix before all extracted name-value pairs. The destination is a file, that uses the format-json template function. Every name-value pair that begins with a dot (".") character will be written to the file (dot-nv-pairs). The log line connects the source, the destination, and the parser.
source s_auditd { file(/var/log/audit/audit.log flags(no-parse)); }; destination d_json { file( "/tmp/test.json" template("$(format-json .auditd.*)\n") ); }; parser p_auditd { linux-audit-parser (prefix(".auditd.")); }; log { source(s_auditd); parser(p_auditd); destination(d_json); };
You can also define the parser inline in the log path.
source s_auditd { file(/var/log/audit/audit.log); }; destination d_json { file( "/tmp/test.json" template("$(format-json .auditd.*)\n") ); }; log { source(s_auditd); parser { linux-audit-parser (prefix(".auditd.")); }; destination(d_json); };
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