Auditd : Add Audit Rules2024/06/18 |
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It's possible to add your own Audit rules like follows. |
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| [1] | For example, Configure Audit rule that records writing and attributes change for [/etc/hosts]. |
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# display current rules (no rules by default like follows) root@dlp:~# auditctl -l No rules # -p [r|w|x|a] : specify target action for Audit # r=read, w=write, x=execute, a=attributes # -k [words] : set keys for searching logs root@dlp:~# auditctl -w /etc/hosts -p wa -k hosts_change root@dlp:~# auditctl -l -w /etc/hosts -p wa -k hosts_change |
| [2] | When some actions are set and it is detected by new Audit rules, Audit logs are recorded like follows. |
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root@dlp:~# ausearch -k hosts_change | aureport -f -i File Report =============================================== # date time file syscall success exe auid event =============================================== 1. 06/17/2024 02:33:28 /etc/hosts~ rename yes /usr/bin/vim.basic ubuntu 342 2. 06/17/2024 02:33:28 /etc/hosts openat yes /usr/bin/vim.basic ubuntu 343 3. 06/17/2024 02:33:28 (null) fchmod yes /usr/bin/vim.basic ubuntu 344 4. 06/17/2024 02:33:28 /etc/hosts setxattr yes /usr/bin/vim.basic ubuntu 345 5. 06/17/2024 02:34:08 /etc/hosts~ rename yes /usr/bin/vim.basic root 375 6. 06/17/2024 02:34:08 /etc/hosts openat yes /usr/bin/vim.basic root 376 7. 06/17/2024 02:34:08 (null) fchmod yes /usr/bin/vim.basic root 377 8. 06/17/2024 02:34:08 /etc/hosts setxattr yes /usr/bin/vim.basic root 378 |
| [3] | Rules added by [auditctl] command are not kept after restarting System, so it needs to add them in a file under [/etc/audit/rules.d] if you'd like to keep persistently. It's OK to add rules to any file name you like under [/etc/audit/rules.d], but extension should be [.rules]. |
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# output current rules to [additional.rules] root@dlp:~# auditctl -l >> /etc/audit/rules.d/additional.rules |
| [4] | If you set a directory for Audit Target, all files are targeted recursively under the directory. |
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# set Audit rule (reading) to [/home/testdir/] root@dlp:~# auditctl -w /home/testdir/ -p r -k testdir_audit root@dlp:~# auditctl -l -w /etc/hosts -p wa -k hosts_change -w /home/testdir -p r -k testdir_audit # logs are recorded like follows root@dlp:~# ausearch -k testdir_audit | aureport -f -i File Report =============================================== # date time file syscall success exe auid event =============================================== 1. 06/17/2024 02:35:50 /home/testdir sendto yes /usr/sbin/auditctl root 184 2. 06/17/2024 02:37:04 /home/testdir/testfile.txt openat yes /usr/bin/vim.basic ubuntu 213 3. 06/17/2024 02:37:04 /home/testdir/testfile.txt readlink no /usr/bin/vim.basic ubuntu 214 4. 06/17/2024 02:37:04 /home/testdir/.testfile.txt.swp openat yes /usr/bin/vim.basic ubuntu 215 5. 06/17/2024 02:37:04 /home/testdir/.testfile.txt.swx openat yes /usr/bin/vim.basic ubuntu 216 6. 06/17/2024 02:37:04 /home/testdir/.testfile.txt.swp openat yes /usr/bin/vim.basic ubuntu 217 7. 06/17/2024 02:37:04 /home/testdir/testfile.txt openat yes /usr/bin/vim.basic ubuntu 218 8. 06/17/2024 02:37:09 /home/testdir/testfile.txt getxattr no /usr/bin/vim.basic ubuntu 219 9. 06/17/2024 02:37:09 /home/testdir/testfile.txt~ listxattr yes /usr/bin/vim.basic ubuntu 220 10. 06/17/2024 02:37:13 /home/testdir lgetxattr no /usr/bin/ls ubuntu 223 11. 06/17/2024 02:37:13 /home/testdir listxattr yes /usr/bin/ls ubuntu 224 12. 06/17/2024 02:37:36 /home/testdir lgetxattr no /usr/bin/ls root 244 13. 06/17/2024 02:37:36 /home/testdir listxattr yes /usr/bin/ls root 245 14. 06/17/2024 02:37:39 /home/testdir/ lgetxattr no /usr/bin/ls root 248 15. 06/17/2024 02:37:39 /home/testdir/ listxattr yes /usr/bin/ls root 249 16. 06/17/2024 02:37:39 /home/testdir/ openat yes /usr/bin/ls root 250 17. 06/17/2024 02:37:39 /home/testdir/testfile.txt lgetxattr no /usr/bin/ls root 251 18. 06/17/2024 02:37:39 /home/testdir/testfile.txt listxattr yes /usr/bin/ls root 252 19. 06/17/2024 02:37:39 /home/testdir/. lgetxattr no /usr/bin/ls root 253 20. 06/17/2024 02:37:39 /home/testdir/. listxattr yes /usr/bin/ls root 254 21. 06/17/2024 02:37:55 /home/testdir/testfile.txt openat yes /usr/bin/cp root 255 |
| [5] | For example, Set Audit rule that monitors files removed by users who has over UID 1000. |
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root@dlp:~#
auditctl -a always,exit -F arch=b64 -S unlink,unlinkat -F 'auid>=1000' -F 'auid!=-1' -F key=delete_audit root@dlp:~# auditctl -l -w /etc/hosts -p wa -k hosts_change -w /home/testdir -p r -k testdir_audit -a always,exit -F arch=b64 -S unlink,unlinkat -F auid>=1000 -F auid!=-1 -F key=delete_audit # logs are recorded like follows root@dlp:~# ausearch -k delete_audit | aureport -f -i File Report =============================================== # date time file syscall success exe auid event =============================================== 1. 06/17/2024 02:40:28 /run/user/1000/systemd/ unlink no /usr/lib/systemd/systemd ubuntu 279 2. 06/17/2024 02:40:28 /run/user/1000/systemd/ unlink no /usr/lib/systemd/systemd ubuntu 280 3. 06/17/2024 02:40:34 /home/testdir/testfile.txt unlinkat no /usr/bin/rm ubuntu 287 4. 06/17/2024 02:40:54 /home/testdir/testfile.txt unlinkat yes /usr/bin/rm ubuntu 295 5. 06/17/2024 02:41:06 /run/user/1000/systemd/units/invocation:dbus.socket unlink yes /usr/lib/systemd/systemd ubuntu 300 6. 06/17/2024 02:41:06 /run/user/1000/systemd/units/invocation:gpg-agent-ssh.socket unlink yes /usr/lib/systemd/systemd ubuntu 301 |
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