Aug 28, 2017 I am a new Linux user. I would like to disable a password for an account. How do I delete user Password under Linux operating system using command line option? All user passwords are stored in /etc/shadow file. The quick way to remove/delete a user password is pass.
For each new mount point you create manually, you can set its partitioning scheme from the drop-down menu located in the left pane. This file system should be sized based on the amount of data that will be stored locally, number of users, and so on. This will enable you to reinstall CentOS without erasing user data files. If you select. Jul 29, 2017 Notes:If multiple users need different level of access to the Samba share, use 'multiser' option and the user with lowerest access in the creds file As systemd recognises that nfs nfs4 and cifs are network based file systems - the option 'netdev' is not needed. This will allow your users who are part of the active directory group 'linuxusers' to perform elevated tasks on the server via sudo. The NOPASSWD can be replaced with ALL which will cause the server to ask the user again for their password. Install the Ambari agents manually on RHEL-CentOS-Oracle 7. Install an Ambari agent on each host in your cluster. On every host in your cluster, use a command line editor to do the following steps. Install the Ambari Agent. Yum install ambari-agent. Using a text.
Linux is known for one of most secure Unix Operating System (OS) in world. But that is not mean it is 100% secure there is say in Information Technology (IT) no technology is a completely secure that is why from a System Administrator to CIO they take measure for securing IT infrastructure on regular basis by applying Personal Security, Hardware Security and Software Security.
In this tutorial we won’t discuss on these topics as these are beyond the scope of this topic. So let’s come on topic Linux Operating system security, weak password policy is one of main flaw for Linux based system as weak password can easily be cracked and causes breach of security. Attacker can crack the weak password easily and could exploit your Linux based systems which could be hosting your company critical database or e-commerce web service.
In this tutorial I will describe how to set password policy like password length, password complexity, password expiration period, deny past used passwords. etc. for CentOS / RHEL based system.
Note: For this tutorial I am using CentOS 6 and CentOS 7 virtual machines on KVM. Password policy configuration done on CentOS 6 and CentOS 7 machine will be same for RHEL 6 and RHEL 7 as well. Also I suggest before configuring files or executing any password policy configuration commands take backup of configuration files.
Password Policy Configuration in CentOS and RHEL machines
As mentioned above in this tutorial password policy configurations will contain below topics:
1. Password Length
2. Password Complexity
3. Password expiration
4. Deny past used passwords.
2. Password Complexity
3. Password expiration
4. Deny past used passwords.
1. Password length configuration
CentOS 6 / RHEL 6
In CentOS 6 or RHEL 6 from root or sudo privileged edit the files /etc/pam.d/system-auth and /etc/pam.d/password-auth through your desire text editor.
Locate the below line in both files and add the parameter minlen=8 at the end of the line.
Below configuration example is from my CentOS 6 machine.
CentOS 7/ RHEL 7
In CentOS 7 and RHEL 7 execute below command for setting up password length:
To verify configured password length after above command execution use below command:
Below sample output is from my CentOS 7 machine.
2. Password Complexity
Password complexity policy allow user to set complex password this policy allow user to use password which contain upper-case character, lower-case character and special or symbol character. In below steps I will configure one upper-case, lower-case, and a special character in the password. You can set any number of maximum allowed upper-case, lower-case, and other letters in your password. So let’s start.
CentOS 6 / RHEL 6
Locate the below line in these files /etc/pam.d/system-auth and /etc/pam.d/password-auth and edit the parameters dcredit=-1 (one digit) ucredit=-1 (one upper-case character) lcredit=-1 (one lower-case character) ocredit=-1 ( one other or sysmbol character):
Below sample output of these files /etc/pam.d/system-auth and /etc/pam.d/password-auth from my CentOS 6 machine:
CentOS 7 / RHEL 7
In CentOS7 or RHEL 7 we will use same authconfig command to configure complex password.
To set at least one lower-case character for password:
To set at least one upper-case character for password:
To set at least one digit for password:
To set at least one other or symbol character for password:
To verify password complexity setting after running above command, use below command:
Below sample output from my CentOS 7 machine:
3. Password expiration
Password expiration policy prompt user to change his/her password before certain days of expiration to enforce this policy CentOS 6 / RHEL 6 and CentOS 7 / RHEL 7 has a file /etc/login.defs. This file contain below parameters which allow System Administrator to set policy:
• PASS_MAX_DAYS: Maximum number of days a password may be used.
• PASS_MIN_DAYS: Minimum number of days allowed between password changes.
• PASS_WARN_AGE: Number of days warning given before a password expires.
• PASS_MIN_DAYS: Minimum number of days allowed between password changes.
• PASS_WARN_AGE: Number of days warning given before a password expires.
To enforce this password in these CentOS 6 / RHEL 6 and CentOS 7 / RHEL 7 machines locate the below parameters in /etc/login.defs file and provide number of days as per your requirement:
Below is sample output from my CentOS 6 and CentOS 7 machine:
Note: This above password expiration policy only applicable to newly created users whereas above password expiration policy won’t be applicable to existing user(s) thus you need to set this policy manually to existing user(s) from chage command you can set policy manually:
• To set Maximum password days: chage -M <no. of days> <username>
• To set Minimum password days: chage -m <no. of days> <username>
• To set number of warning days before password expire: chage -W <no. of days> <username>
Sample output:
• To set Minimum password days: chage -m <no. of days> <username>
• To set number of warning days before password expire: chage -W <no. of days> <username>
Sample output:
Centos Make User Admin
If you have more then one existing users you can use add those users in text file and with help of for loop command you can set the policy manually below is sample from my machine:
4. Deny past used passwords
Deny past used passwords policy disallow users to set their password which were used in past. This make password more complicated by making it non guessable for attacker. In both CentOS 6 / RHEL 6 and CentOS 7 / RHEL 7 configuration is same. In both OSes you need to configure these files /etc/pam.d/system-auth and /etc/pam.d/password-auth locate and make below entry:
Sample output:
Centos Username And Password
2,124 total views, 16 views today