Questions regarding password-based authentication and password management

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7
votes
3answers
13k views

How to take 'password' like input in shell script? [duplicate]

Possible Duplicate: How to hide commands typed in a Linux shell? Reading passwords without showing on screen in Bash Scripts I would like to take a password as input, but I want user to ...
7
votes
2answers
9k views

How to expire a password? (For inital account creation)

I've often created temporary passwords for users for my own development machine for initial id creation. For other environments, I've seen admins have the ability to have a password show as expired ...
7
votes
3answers
706 views

Root and my password are the same

If I cat /etc/shadow I can get the encrypted passwords of root and my user. These passwords are the same (I know, bad security) for each account, but in /etc/shadow they show up as being different ...
7
votes
2answers
6k views

Why is sudo telling me my password is wrong?

I recently installed OpenBSD 4.9 in my computer, so I could learn a little bit about Unix-like operating systems. I added a new user to the system called bruno. Ok. When I use the 'sudo' command, it ...
7
votes
3answers
2k views

Why does my sudo ask for password only once but evaluate thrice?

$ sudo some_command Password: Sorry, try again. Sorry, try again. Sorry, try again. sudo: 3 incorrect password attempts $ This is what my shell prints when I enter a wrong password to a sudoed ...
7
votes
4answers
1k views

How to set up two-factor authentication with OTP on FreeBSD?

I have a FreeBSD hosted server that I like to be able to get to from anywhere. Normally I use SSH publickey to log in, or if I don't have my SSH private key available then I might use regular password ...
6
votes
5answers
13k views

Can I change root password by sudo, without su?

I can sudo, but I don't have the root password so I can't su root. Using sudo, can I change the root password?
6
votes
3answers
671 views

Is w command safe for users?

Some applications allow to pass password as an argument. For example: mysql --user=user_name --password=your_password db_name Is it safe? Besides the fact that typed password would be saved in bash ...
6
votes
4answers
2k views

Is it possible to change password database file(/etc/passwd) in linux?

Is it possible to change password database file(/etc/passwd) to some other file. How does this authentication mechanism work internally ? Does it depend on pam ?
6
votes
1answer
363 views

How can I prevent someone from gaining root access through the bootloader?

On Ubuntu 10.10 I can login as root without the root password by replacing ro quiet splash with rw init=/bin/bash. How can I secure my machine and disable this backdoor?
6
votes
2answers
2k views

Pipe Password to Application When Asked

The following should be done in a bash script: curl --digest --user schmijos https://bitbucket.org/u/p/get/tip.zip -o tip.zip How can I automatically submit a password to curl when it asks for it? ...
6
votes
1answer
6k views

export HTTP_PROXY and special characters in passwd

Suppose for the sake of argument my password below is abc123@ I need to authenticate my linux machine through a corporate proxy to get patches and updates... normally I'd use this: export ...
6
votes
4answers
3k views

SSH authentication: either SSH keys or one time password

I have an Ubuntu 10.04 Linux server that I normally ssh into (from my home machine) using ssh key authentication. However, sometimes I need to ssh remotely from potentially insecure machines (like ...
6
votes
3answers
266 views

Passwords for newly created users?

I am fairly new to Linux and I have question regarding users. When I use the useradd command I don't specify a password. I must use the passwd command afterwards. Does this mean that the user is ...
6
votes
1answer
151 views

Why do we need an expiration period?

Why is there a gap between the expiration of an account and its complete deactivation, when one can no longer log in or change his password when it became expired?
6
votes
4answers
372 views

How to log into database via script securely?

I am wondering about whether it is acceptable (security-wise) to have database login credentials (user/pass) set in an environment variable or passed in as a command-line parameter? Both of these ...
6
votes
1answer
2k views

GNOME-keyring KWallet integration?

I use some GNOME apps, and some KDE apps, so some of them use G-keyring and some KWallet... What I would like to have is a single place for managing passwords. Is there a way to integrate G-keyring ...
6
votes
3answers
68 views

different passwords depending on plugged-in devices

I would like to have different passwords for my account(s): When (e.g.) a certain USB stick is plugged in then an easy password is to be used. The idea is: If I leave my computer then I take the stick ...
6
votes
3answers
2k views

Logged on via ssh-key, can I reset my account password?

I am logged in on a server via sshkey (ssh -i /home/me/.ssh/ssh-key me@server). I got sudo rights on that server from the admin, but I can't exercise them, since I forgot my actual Unix password (or ...
6
votes
2answers
108 views

Linux graphical password dialog trick security

When we run a command by sudo, the password is asked [sudo] password for user If the sudo is not typed the password should not be asked. If asked, I would assume it as a fraud by the application. ...
6
votes
1answer
339 views

Any random password results in successful login on tty

I can login to my machine (FreeBSD 9.1-RELEASE) for any user (for example: root or operator or any that exists in /etc/passwd) with any random password that I type... I tried to reset password for ...
6
votes
1answer
226 views

epiphany plugin for password storage

I am looking for a keepass plugin for epiphany. Something like PassIFox for Firefox: PassIFox "behaves" like a new password storage for firefox - and redirects all queries (fetch/store etc..) to ...
5
votes
3answers
2k views

Stracing su and ssh shows the password. Is this a security flaw or am I missing something?

I'm currently fascinated by strace so, being new to it, I decided to play around a little. As suggested by the question title, I tried both strace su and strace ssh. Both commands displayed the ...
5
votes
3answers
500 views

Does the shadow file have encrypted passwords?

man 5 shadow says this about the 2nd field: encrypted password Is that true nowadays? I think it should say "hashed password". Am I correct?
5
votes
4answers
122 views

How do I put comments in my /etc/shadow file?

I am running through some system upgrades and my package manager is showing changes between the upstream /etc/shadow and mine. I would like to put some comments in the file for next time this ...
5
votes
3answers
4k views

Why is the 'sudo' password different than the 'su root' password

On my personal machine, I often type sudo in front of certain commands in order to accomplish administrative tasks. I had hoped to avoid doing this throughout the day, by typing su root and providing ...
5
votes
2answers
6k views

Two ways to lock a password but only one to unlock

CentOS 6 Linux has two ways to lock a password: passwd -l usermod -L Today I found out, that they do something different. passwd writes two exclamation marks into the shadow file. # passwd -d ...
5
votes
3answers
1k views

Remote shell script Enter passphrase for

How can I run a script to log into a remote server and execute a remote ssh command without entering in my passphrase? For example: When I log onto a remote server and execute the git pull command I ...
5
votes
2answers
979 views

How to disable the try again password in ssh command

I want the ssh command to only allow one chance in typing the password, if the password was wrong at the first time the ssh will return Permission denied (publickey......). Is there a flag that ...
5
votes
1answer
1k views

Not able to set password in ArchLinux

I logged in as root and created a new account: # useradd -d /home/onie -m onie # su onie Now I try to set the password for onie myself using the passwd command, but it's asking for my current ...
5
votes
2answers
476 views

How to set default password algorithm to sha512 on Linux?

on AIX, it would be a simple: chsec -f /etc/security/login.cfg -s usw -a pwd_algorithm=ssha512 Question: But how can we set the default password algorithm to sha512? UPDATE: I think pwd_algorithm ...
5
votes
1answer
462 views

No password to run command as root for fixed command? [duplicate]

Is it possible to define a rule in sudoers to allow one user to run one well defined command as root, without password or other authentication except being the right user? Are there alternatives to ...
5
votes
4answers
4k views

Force Firefox to remember passwords on particular sites

Usually, when I log into a website with username and password, Firefox asks whether it should remember the login details. When I click yes, next time I visit the website, the username and password ...
5
votes
2answers
1k views

How to check for empty passwords?

Looking at all the ssh-login attempts by script-kiddies I assume that there are messed up systems connected to the internet that have password-less accounts set up. But how to check a Linux/Unix ...
5
votes
2answers
479 views

Why is 8 numbers considered a “strong” password?

Just curious as to why 8 numbers are accepted as a password in linux (CentOS if it matters) and not 8 characters on a non-dictionary word. It's 10 vs 26 per digit after all. (52 counting CaSe ...
5
votes
1answer
111 views

Is it safe for my ssh user to be given passwordless sudo for `apt-get update` and `apt-get upgrade`?

I have an SSH standard user account on my personal server, and it has sudo access (via its password). I ssh in using a public key, so I don't have to type in the account password to log in. Is it ...
5
votes
1answer
466 views

sudo testing for credentials

I have a working bash script, that may run from 0 to 8-9 minutes. It requires sudo if it finds a problem and needs to change permissions/ownership on a file. I do not want to wait for the sudo prompt, ...
5
votes
2answers
1k views

How to see password as we type it

In debian wheezy terminal i type su - It ask for password, which i type but it dont show anything as Password: I want to it to show at least some asterisks as the placeholder for the password ...
5
votes
1answer
4k views

How to reset KDE wallet password in linux?

I have installed OpenSUSE on my laptop. I am trying to connect to my wifi. I entered my wifi password (correctly) and then it is asking for my KDE wallet password. I set the KDE password but forgot ...
5
votes
2answers
4k views

Graphically ask for password in a bash script and retain default sudo timeout setting

The sudo -A (SUDO_ASKPASS) option apparently causes sudo to lose the timeout (e.g., timestamp_timeout) setting. I want to use the sudo -A option but I want to retain the default timeout (e.g., 15 ...
5
votes
1answer
335 views

Automated ssh login with passphrase?

Logging onto a machine over ssh typically requires a password to be entered before access is granted. Alternatively, a key/certificate (without a passphrase) can be installed onto the remote machine ...
5
votes
2answers
4k views

Another account with same uid as root gets prompted to set new password for root, not itself

After upgrading the os from 5300-06 to 5300-11, this weird behaviour happened. My system had another unix account, let's call it "abc", purposely configured its uid to 0 for working as a root with ...
5
votes
2answers
4k views

Why SSH is asking for my private key password each time

Since yesterday, each time I try to connect to an ssh server, I got asked for my password. What should I do to make SSH not ask for my password each time.
5
votes
1answer
3k views

Changing password in multiple boxes using script

I'm working in a environment which has around 400 AIX boxes. I don't have root access and I'm a normal user. The environment has no LDAP kind of centralized mechanism for authentication so the ...
5
votes
1answer
4k views

Preventing `passwd` for asking for the local password

I have setup the sever to only use LDAP for authentication by using authconfig-tui. Everything works well but, when I run passwd, I get two prompts for a password: [beamin@rhel6-test-server1 ~]$ ...
5
votes
4answers
2k views

automatic passwordless ssh at login/restart

I want to have passwordless ssh to persist even after after I restart or logoff and then login. Somehow I have to run ssh-agent and use command ssh-add at login. In a tutorial I read that I should add ...
5
votes
1answer
770 views

Save password in bash script for multiple queries

I would like to know if there is a safe way to only be queried for a password once in a custom bash script, and then save it somehow to be used for later needs. At the end of the script it should be ...
5
votes
1answer
2k views

Samba passwords expiring in x days - how do we fix them to not expire

We use OpenLDAP and Samba v3. Recently some Samba-defined users (no accounts on the shared linux server) started being listed in logwatch as having their passwords come up to "will expire"...I ...
5
votes
2answers
2k views

Can KWallet manage my ssh passwords?

I need a way to store some SSH passwords. Note that these are login passwords which I need to pass to ssh; key authentication is unfortunately not an option. I'd like to be able to have KWallet fill ...
4
votes
3answers
758 views

Any disk encryption that locks itself for some time after a number of failed attempts?

Is there any way to have your disk/partition/file encrypted (in Linux or as a hardware encryption; no Windows here) in such way that it locks itself for say 10 minutes after say 3 failed unlock ...