go-libaudit

go-libaudit is a library for Go (golang) for communicating with the Linux Audit Framework. The Linux Audit Framework provides system call auditing in the kernel and logs the events to user-space using netlink sockets. This library facilitates user-space applications that want to receive audit events.

Installation and Usage

Package documentation can be found on GoDoc.

Installation can be done with a normal go get:

$ go get github.com/elastic/go-libaudit

go-libaudit has two example applications that you can use to try the library. The first is audit which registers to receive audit events from the kernel and outputs the data it receives to stdout. The system's auditd process should be stopped first.

$ go install github.com/elastic/go-libaudit/cmd/audit
$ sudo $GOPATH/bin/audit -d

The second is auparse which parses the log files from the Linux auditd process or the output of the audit example command. It combines related log messages that are a part of the same event.

$ go install github.com/elastic/go-libaudit/cmd/auparse
$ sudo cat /var/log/audit/audit.log | auparse
---
type=CRED_ACQ msg=audit(1481077334.302:545): pid=1444 uid=0 auid=1000 ses=4 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 msg='op=PAM:setcred grantors=pam_env,pam_unix acct="root" exe="/usr/bin/sudo" hostname=? addr=? terminal=/dev/pts/1 res=success'
---
type=USER_START msg=audit(1481077334.303:546): pid=1444 uid=0 auid=1000 ses=4 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 msg='op=PAM:session_open grantors=pam_keyinit,pam_limits acct="root" exe="/usr/bin/sudo" hostname=? addr=? terminal=/dev/pts/1 res=success'
---
type=SYSCALL msg=audit(1481077334.304:547): arch=c000003e syscall=59 success=yes exit=0 a0=7f683953a5d8 a1=7f683953fd38 a2=7f6839543a90 a3=6 items=2 ppid=1444 pid=1445 auid=1000 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts1 ses=4 comm="su" exe="/usr/bin/su" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
type=EXECVE msg=audit(1481077334.304:547): argc=1 a0="su"
type=CWD msg=audit(1481077334.304:547):  cwd="/home/andrew_kroh"
type=PATH msg=audit(1481077334.304:547): item=0 name="/bin/su" inode=5026 dev=08:01 mode=0104755 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:su_exec_t:s0 objtype=NORMAL
type=PATH msg=audit(1481077334.304:547): item=1 name="/lib64/ld-linux-x86-64.so.2" inode=16778495 dev=08:01 mode=0100755 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:ld_so_t:s0 objtype=NORMAL

It supports outputting the messages as plain text (default), JSON, or YAML by using -format=yaml for example.

$ sudo cat /var/log/audit/audit.log | auparse -format=json
---
{"@timestamp":"2016-12-07 02:22:14.302 +0000 UTC","acct":"root","auid":"1000","exe":"/usr/bin/sudo","grantors":"pam_env,pam_unix","op":"PAM:setcred","pid":"1444","raw_msg":"audit(1481077334.302:545): pid=1444 uid=0 auid=1000 ses=4 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 msg='op=PAM:setcred grantors=pam_env,pam_unix acct=\"root\" exe=\"/usr/bin/sudo\" hostname=? addr=? terminal=/dev/pts/1 res=success'","record_type":"CRED_ACQ","result":"success","sequence":"545","ses":"4","subj_category":"c0.c1023","subj_domain":"unconfined_t","subj_level":"s0-s0","subj_role":"unconfined_r","subj_user":"unconfined_u","terminal":"/dev/pts/1","uid":"0"}
---
{"@timestamp":"2016-12-07 02:22:14.303 +0000 UTC","acct":"root","auid":"1000","exe":"/usr/bin/sudo","grantors":"pam_keyinit,pam_limits","op":"PAM:session_open","pid":"1444","raw_msg":"audit(1481077334.303:546): pid=1444 uid=0 auid=1000 ses=4 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 msg='op=PAM:session_open grantors=pam_keyinit,pam_limits acct=\"root\" exe=\"/usr/bin/sudo\" hostname=? addr=? terminal=/dev/pts/1 res=success'","record_type":"USER_START","result":"success","sequence":"546","ses":"4","subj_category":"c0.c1023","subj_domain":"unconfined_t","subj_level":"s0-s0","subj_role":"unconfined_r","subj_user":"unconfined_u","terminal":"/dev/pts/1","uid":"0"}
---
{"@timestamp":"2016-12-07 02:22:14.304 +0000 UTC","a0":"7f683953a5d8","a1":"7f683953fd38","a2":"7f6839543a90","a3":"6","arch":"x86_64","auid":"1000","comm":"su","egid":"0","euid":"0","exe":"/usr/bin/su","exit":"0","fsgid":"0","fsuid":"0","gid":"0","items":"2","pid":"1445","ppid":"1444","raw_msg":"audit(1481077334.304:547): arch=c000003e syscall=59 success=yes exit=0 a0=7f683953a5d8 a1=7f683953fd38 a2=7f6839543a90 a3=6 items=2 ppid=1444 pid=1445 auid=1000 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts1 ses=4 comm=\"su\" exe=\"/usr/bin/su\" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)","record_type":"SYSCALL","result":"success","sequence":"547","ses":"4","sgid":"0","subj_category":"c0.c1023","subj_domain":"unconfined_t","subj_level":"s0-s0","subj_role":"unconfined_r","subj_user":"unconfined_u","suid":"0","syscall":"execve","tty":"pts1","uid":"0"}
{"@timestamp":"2016-12-07 02:22:14.304 +0000 UTC","a0":"su","argc":"1","raw_msg":"audit(1481077334.304:547): argc=1 a0=\"su\"","record_type":"EXECVE","sequence":"547"}
{"@timestamp":"2016-12-07 02:22:14.304 +0000 UTC","cwd":"/home/andrew_kroh","raw_msg":"audit(1481077334.304:547):  cwd=\"/home/andrew_kroh\"","record_type":"CWD","sequence":"547"}
{"@timestamp":"2016-12-07 02:22:14.304 +0000 UTC","dev":"08:01","inode":"5026","item":"0","mode":"0104755","name":"/bin/su","obj_domain":"su_exec_t","obj_level":"s0","obj_role":"object_r","obj_user":"system_u","objtype":"NORMAL","ogid":"0","ouid":"0","raw_msg":"audit(1481077334.304:547): item=0 name=\"/bin/su\" inode=5026 dev=08:01 mode=0104755 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:su_exec_t:s0 objtype=NORMAL","rdev":"00:00","record_type":"PATH","sequence":"547"}
{"@timestamp":"2016-12-07 02:22:14.304 +0000 UTC","dev":"08:01","inode":"16778495","item":"1","mode":"0100755","name":"/lib64/ld-linux-x86-64.so.2","obj_domain":"ld_so_t","obj_level":"s0","obj_role":"object_r","obj_user":"system_u","objtype":"NORMAL","ogid":"0","ouid":"0","raw_msg":"audit(1481077334.304:547): item=1 name=\"/lib64/ld-linux-x86-64.so.2\" inode=16778495 dev=08:01 mode=0100755 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:ld_so_t:s0 objtype=NORMAL","rdev":"00:00","record_type":"PATH","sequence":"547"}

To normalize and interpret the messages, use the -i flag for "interpret". This adds a category to the event and creates the actor, action, thing, and how fields based on data from the event. By default it will resolve UID and GID values to their names (use -id=false to disable this).

$ sudo cat /var/log/audit/audit.log | auparse -format=yaml -i
---
timestamp: 2016-12-07T02:22:14.302Z
sequence: 545
category: user-login
record_type: cred_acq
result: success
session: "4"
summary:
  actor:
    primary: vagrant
    secondary: root
  action: acquired-credentials
  object:
    type: user-session
    primary: /dev/pts/1
  how: /usr/bin/sudo
user:
  ids:
    auid: "1000"
    uid: "0"
  names:
    auid: vagrant
    uid: root
  selinux:
    category: c0.c1023
    domain: unconfined_t
    level: s0-s0
    role: unconfined_r
    user: unconfined_u
process:
  pid: "1444"
  exe: /usr/bin/sudo
data:
  acct: root
  grantors: pam_env,pam_unix
  op: PAM:setcred
  terminal: /dev/pts/1
ecs:
  event:
    category:
    - authentication
    type:
    - info
  user:
    name: vagrant
    id: "1000"
    effective:
      name: root
      id: "0"
    target: {}
    changes: {}
  group: {}

---
timestamp: 2016-12-07T02:22:14.303Z
sequence: 546
category: user-login
record_type: user_start
result: success
session: "4"
summary:
  actor:
    primary: vagrant
    secondary: root
  action: started-session
  object:
    type: user-session
    primary: /dev/pts/1
  how: /usr/bin/sudo
user:
  ids:
    auid: "1000"
    uid: "0"
  names:
    auid: vagrant
    uid: root
  selinux:
    category: c0.c1023
    domain: unconfined_t
    level: s0-s0
    role: unconfined_r
    user: unconfined_u
process:
  pid: "1444"
  exe: /usr/bin/sudo
data:
  acct: root
  grantors: pam_keyinit,pam_limits
  op: PAM:session_open
  terminal: /dev/pts/1
ecs:
  event:
    category:
    - authentication
    type:
    - info
  user:
    name: vagrant
    id: "1000"
    effective:
      name: root
      id: "0"
    target: {}
    changes: {}
  group: {}

---
timestamp: 2016-12-07T02:22:14.304Z
sequence: 547
category: audit-rule
record_type: syscall
result: success
session: "4"
summary:
  actor:
    primary: vagrant
    secondary: root
  action: executed
  object:
    type: file
    primary: /bin/su
  how: /usr/bin/su
user:
  ids:
    auid: "1000"
    egid: "0"
    euid: "0"
    fsgid: "0"
    fsuid: "0"
    gid: "0"
    sgid: "0"
    suid: "0"
    uid: "0"
  names:
    auid: vagrant
    egid: root
    euid: root
    fsgid: root
    fsuid: root
    gid: root
    sgid: root
    suid: root
    uid: root
  selinux:
    category: c0.c1023
    domain: unconfined_t
    level: s0-s0
    role: unconfined_r
    user: unconfined_u
process:
  pid: "1445"
  ppid: "1444"
  name: su
  exe: /usr/bin/su
  cwd: /home/andrew_kroh
  args:
  - su
file:
  path: /bin/su
  device: "00:00"
  inode: "5026"
  mode: "0755"
  uid: "0"
  gid: "0"
  owner: root
  group: root
  selinux:
    domain: su_exec_t
    level: s0
    role: object_r
    user: system_u
data:
  a0: 7f683953a5d8
  a1: 7f683953fd38
  a2: 7f6839543a90
  a3: "6"
  arch: x86_64
  argc: "1"
  exit: "0"
  syscall: execve
  tty: pts1
paths:
- dev: "08:01"
  inode: "5026"
  item: "0"
  mode: "0104755"
  name: /bin/su
  obj_domain: su_exec_t
  obj_level: s0
  obj_role: object_r
  obj_user: system_u
  objtype: NORMAL
  ogid: "0"
  ouid: "0"
  rdev: "00:00"
- dev: "08:01"
  inode: "16778495"
  item: "1"
  mode: "0100755"
  name: /lib64/ld-linux-x86-64.so.2
  obj_domain: ld_so_t
  obj_level: s0
  obj_role: object_r
  obj_user: system_u
  objtype: NORMAL
  ogid: "0"
  ouid: "0"
  rdev: "00:00"
ecs:
  event:
    category:
    - process
    type:
    - start
  user:
    effective: {}
    target: {}
    changes: {}
  group: {}

ECS compatibility

This currently provides Elastic Common Schema (ECS) 1.8 categorization support for some of the more prominent or meaningful auditd events and syscalls.