Questions regarding password-based authentication and password management

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3
votes
2answers
2k views

Second field in /etc/shadow

If the second field of the /etc/shadow file is set to !!, does it mean that the account is disabled? Or does it mean that the account is active with no password assigned?
13
votes
6answers
2k views

Is there a root password on OS X and Ubuntu?

When you setup a new Ubuntu or OS X installation a user is generally created for you. On OS X it is whatever username you pick. On Ubuntu (the server version) usually the ubuntu user is created. The ...
4
votes
1answer
1k views

Password expiry in Samba v3.0

I'm trying to setup a Samba server which asks new users to change their password on their first login and makes passwords expire after 90 days. I was able to setup the 90 days expiry date but the ...
4
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 ...
4
votes
2answers
378 views

Is it possible (and a good idea) to do `pw lock root` on FreeBSD?

I have set up sudo on my FreeBSD server. As I now never want to log in as root anymore, I was wondering whether I should do sudo pw lock root. My questions are: Is this possible, without forever ...
3
votes
2answers
7k views

Will a users password expire if I set the “maxexpired” to “-1”? [maxage not 0] - AIX

So under AIX 6, according to "lsuser" the user has the following settings: maxexpired=-1 maxage=2 So this means that 2 weeks after the last password update of the user the password will expire, but ...
3
votes
4answers
1k views

Why can't I echo the password to fetchmail?

I'm trying to configure a fetchmail. Before I deal with the syntax of fetchmailrc ( I discovered that the level of bugginess of a problem is synergistic with the number of different aspects of the ...
6
votes
1answer
203 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 ...
3
votes
1answer
998 views

Why does a user get prompted for password under AIX?

Users get prompted for password, and according to the lsuser -f username output: expires=0 maxexpired=-1 maxage=13 users shouldn't be prompted for changing password. Why does he has a change ...
0
votes
3answers
25k views

How to check that a user/password is expired in AIX?

I can check that the user is expired or not with: lsuser -f USERNAME | fgrep expires But how can I check that the user's password is expired or not? Are there any other "expiring" things that can ...
7
votes
2answers
5k 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 ...
4
votes
2answers
2k views

/etc/shadow date of last password change—UTC or local time?

man 5 shadow gives the following description of the third field in each line: The date of the last password change, expressed as the number of days since Jan 1, 1970. The value 0 has a ...
10
votes
4answers
21k views

How to check password with Linux?

I want to check, from the linux command line, if a given cleartext password is the same of a crypted password on a /etc/shadow (I need this to authenticate web users. I'm running an embedded linux.) ...
2
votes
4answers
646 views

sudo without password - security? [duplicate]

Possible Duplicate: What specific vulnerabilities am I creating by disabling the sudo password? I'm involved yet again in the old argument on whether sudo without password is secure enough ...
29
votes
5answers
31k views

Disable a user's login without disabling the account

Let's say I create a user named "bogus" using the adduser command. How can I make sure this user will NOT be a viable login option, without disabling the account. In short, I want the account to be ...
10
votes
3answers
2k views

How do I log into my Linux laptop if I have forgotten both the login and password?

How do I log into my Linux laptop if I have forgotten both the username and password?
8
votes
1answer
173 views

Does ssh-agent store my passphrase?

Is it possible to determine the passphrases of private keys added to ssh-agent? I'm thinking along the lines of someone with root privileges trying to find out my passphrase after I have added the ...
5
votes
2answers
1k 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 ...
6
votes
1answer
348 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?
7
votes
3answers
12k views

How to get back sudo on Ubuntu?

I have done this: sudo chown -R myname /usr/ and now I can't use the sudo command because of this error: sudo: must be setuid root And as I read this means that the owner of this file ...
2
votes
1answer
788 views

root password changed automatically

I have my system on dual boot (win7 and RHEL 6). I have 2 user account on RHEL 6. A normal user and a root user. I put passwords of both accounts same. It was working fine from 5 6 days. Yesterday I ...
3
votes
2answers
810 views

Is Open LDAP meant to work with the passwd command for Linux?

I've implemented an Open LDAP server in OpenSuSE 11.2 via the YaST GUI. I'm having success logging in from the local machine and other machines via LDAP. I am able to change LDAP user passwords via ...
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 ...
3
votes
1answer
798 views

Debian wake up from suspend password

I am using Debian Squeeze. When I suspend my laptop and wake it up again later, it doesn't ask for the system password. How do I fix this?
1
vote
0answers
856 views

Backupninja + Duplicity problem

I have recently installed on a Debian squeeze_64 server the Backupninja and Duplicity utilities. My goal is to backup /foo/bar/* to /desti/nation/ with full backup once a week and differentially once ...
1
vote
1answer
621 views

Fedora 15 won't remember wireless password

I just installed Fedora 15 beta with Gnome 3. I've done all the updates. The networking applet asks for the wireless password every time it connects. I found this bug, which says that the issue is ...
2
votes
1answer
416 views

A local, centralized, secure way to store FTP login data, including passwords

I want to be able to store the login details all of my remote FTP accounts in one place, securely. Then I'd like clients like autofs/curlftpfs, Filezilla, etc to use this one store of passwords. I'm ...
2
votes
1answer
625 views

retrieve password on remote server

I normally ssh into a remote server, for which I previously set an option that allows me not to type my password every time. Now that I forgot it, is there any way to retrieve it?
3
votes
3answers
899 views

Why does this password fail AIX and Solaris rules

Had to reset my password on a couple of client servers today, and despite following the rules I get the message "Your password failed to meet: minimum of 2 non-alphabetic characters" back from the ...
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 ...
2
votes
1answer
863 views

gnome-screensaver-command --lock, hide password

If I lock the screen using gnome-screensaver (gnome-screensaver-command --lock) and enter the password, a big dot is shown instead of each character. Is it possible to change this behaviour such that ...
1
vote
1answer
636 views

crypt() on different machines

Because of a hardware issue i need to migrate many virtual users to a new machine. Their passwords stored in MySQL encrypted with ENCRYPT which using crypt()eventually. Maybe it's my fault but salt ...
2
votes
1answer
891 views

Does OpenBSD use bcrypt by default?

http://codahale.com/how-to-safely-store-a-password/ with what does OpenBSD store the password by default? They say bcrypt is way more secure then hashing. I googled' it and obsd supports bcrypt, but ...
16
votes
3answers
41k views

How do you change the root password on Debian?

I want to change the password I assigned to root on my Debian webserver to something longer and more secure. Bit of an obvious newbie question, but how do I do that? I haven’t forgotten/lost the ...
6
votes
5answers
9k 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?
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
2answers
3k views

Forcing sudo to prompt for a password

If I do the following: sudo su - //enter password exit exit //login again straight away sudo su - The second invocation of sudo does not request a password because even though I have logged out ...
2
votes
2answers
2k views

How to get hashed password in /etc/shadow using getpwnam()?

Apparently there is a function (getpwnam) that given a username, will return the appropriate entry in /etc/passwd with the other details for that user (shell, uid, gid, etc.). However, I have no idea ...
9
votes
1answer
4k views

What methods are used to encrypt passwords in /etc/passwd and /etc/shadow?

A careful examination of the /etc/passwd and /etc/shadow files reveal that the passwords stored are hashed using some form of hashing function. A quick Google search reveals that by default, the ...
10
votes
3answers
3k views

How can I make a user able to log in with ssh keys but not with a password?

I would like to create a user and have no password. As in you cant log in with a password. I want to add keys to its authorized_keys by using root. This is for my automated backup system.
3
votes
1answer
727 views

Change default for Nautilus (file_manager) from “Forget password immediately”?

When opening a tab which needs to mount a Samba share, Nautilus 2.30.1 displays a window: Password required for share xxx on localhost Password: [ ] (*) Forget password immediately ( ) ...
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 ...
7
votes
7answers
1k views

Is there a way to store Firefox passwords in a local encrypted database in Linux?

I want Firefox to "remember" my passwords so I don't have to type them in; unfortunately, the built-in password manager stores them in plain text, which is too high a security risk. I'd like to find a ...
14
votes
4answers
450 views

What specific vulnerabilities am I creating by disabling the sudo password?

Here are some instructions on how to disable your sudo password. These carry the following warning If you disable the sudo password for your account, you will seriously compromise the security of ...
7
votes
5answers
20k views

Program for decrypt linux shadow file

Is there any program or script available for decrypt Linux shadow file ?
1
vote
1answer
1k views

How to reset Linux root and grub passwords?

If we forget our Linux root password, we can change it by changing grub's boot options. But in this case, we also set a grub password and forgot both passwords. How can we recover both?
4
votes
3answers
248 views

Randomise or shred memory of an application

Is it possible to randomise or shred memory of a particular application just after its life ends, or better, whenever it deallocates some memory? A command-line utility like this would be perfect: ...
46
votes
2answers
11k views

Why is there a big delay after entering a wrong password?

I notice a weird (well, according to me) thing about passwords. For example, if I type an incorrect password during login, there will be a few seconds' delay before the system tells me so. When I try ...
12
votes
3answers
756 views

How can I tell *which* application is asking for access to gnome-keyring/Seahorse?

Whenever I log in on Ubuntu Lucid Lynx 10.04 I get a Seahorse/gnome-keyring prompt telling me an application wants to access my keyring. It isn't the network manager, because if I cancel the request ...
5
votes
2answers
470 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 ...