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Lab 9.2 Locking Accounts after Excessive Login Attempts

Posts: 24
edited June 2021 in LFS216 Class Forum

I think current contents of Lab 9.2 seems not to work in CentOS8 environment, and I think the contents should be updated.
At least,

  1. pam_tally2 is absolete, instead **pam_faillock **is recommended
  2. You shouldn't modify manually password-auth/system-auth files ( it's prohibited to do so in the files)
  3. You should use **authselect **command instead ( **authconfig **is an older command)

in short, It's better to excercise this Lab

  • Use pam_faillock **, not **pam_tally2
  • Use authselect and modify configuration _indirectly _

[What I did ]

  1. create authselect user profile from current sssd profile
  1. [root@main ~]# authselect create-profile test-lab -b sssd (profile name is test-lab)
  1. change the profile to above with faillock feature
  1. [root@main ~]# authselect select custom/test-lab with-faillock without-nullok
  2. [root@main ~]# authselect current
  3. Profile ID: custom/test-lab
  4. Enabled features:
  5. - with-faillock
  6. - without-nullok
  1. change password-auth/system-auth indirectly
  1. [root@main ~]#vim /etc/authselect/custom/test-lab/password-auth
  2. [root@main ~]#vim /etc/authselect/custom/test-lab/system-auth

i set deny counts to twice (deny=2), unlock_time to 0 (infinite) (see [Reference sites][1])

  1. apply above chaanges
  1. [root@main ~]#authselect apply-changes
  1. Try
    ( I already set password to failuser previously.)
  1. [root@main ~]# ssh failuser@localhost
  2. failuser@localhost's password:
  3. Permission denied, please try again.
  4. failuser@localhost's password:
  5. Permission denied, please try again.
  6. failuser@localhost's password:
  7. failuser@localhost: Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).

**Note : password prompt appears 3 times. this is sshd behavior not faillock's. if you change prompt number, you add option like;

ssh failuser@localhost -o 'NumberOfPasswordPrompts 5'

  1. Check by faillock
  1. [root@main ~]# faillock
  2. failuser:
  3. When Type Source Valid
  4. 2021-06-27 17:43:12 RHOST ::1 V
  5. 2021-06-27 17:43:15 RHOST ::1 V
  6. gdm:
  7. When Type Source Valid
  8. root:
  9. When Type Source Valid
  10. student:
  11. When Type Source Valid

the user "failuser" failes twice. this means the user locked. (BTW I don't know how to see the user is locked or not)

  1. Unlock the user
    [root@main ~]# faillock --user failuser --reset

[Reference sites]

[1] https://i66lab.com/User:xltran/App/CentOS/8/Administration/Authselect
[2] https://michaelpesa.com/posts/creating-custom-authselect-profiles/
[3] https://www.golinuxcloud.com/pam-faillock-lock-user-account-linux/

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