Here’s a tip to restrict normal user account access so that common users may not be able to explore other directories beyond his/her own /home directory.
- First you need to chmod all /home dir to 0700
- Then, you need to set the default umask to 077, to do that, you ned to edit /etc/profile, and replace “umask 022” with “umask 077“.
- Optionally, you can also update PAM configuration in /etc/pamd.d/common-session so that the line reads “pam_umask.so umask=077 usergroups“
The tips has been adapted from – superuser.com
One of the factor that makes your system easily crackable is the weak password. PAM cracklib forces users to choose stronger password by analyzing the password strength, length and entropy.
To enable pam_cracklib in Debian / Ubuntu operating system, you need to install libpam_cracklib:
sudo apt-get install libpam_cracklib
Then edit the “/etc/pam.d/common-password” file using your favorite editor. Then, add and uncomment the following line at the end of the file.
password required pam_cracklib.so retry=3 minlen=6 difok=3
difok determines the number of same characters that allowed to be present in the old and new passwords.