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43
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 ...
23
votes
6answers
7k views

Can I find out which ssh key was used to access an account?

Is it possible to find out which ssh key was used to access an account? I have an account on a server that I let several (trusted!) people have access to via ssh. I'd find it useful to be able to ...
14
votes
2answers
1k views

SSH ignores characters after correct password string?

Remote machine 10.10.10.1 has password "asdFGH12" for user named "user". I'm able to log in even if I type in password "asdFGH12dasdkjlkjasdus" or any other characters after the "asdFGH12" string. $ ...
14
votes
2answers
610 views

How do I tell what program is asking for a password?

I'm getting an occasional "Authentication request" dialog from Gnome, and I don't know what program is asking or even which account it's talking about. [email redacted] is an email address of mine, ...
11
votes
3answers
586 views

Groups differ from the local ones when logging in remotely

We store our users in LDAP, alongside some groups that have meaning across different systems (organizational roles including wheel). There are also groups local to workstations, e.g. audio or video ...
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.
10
votes
3answers
1k views

How can I lock my own account from remote ssh login with password?

I don't want to disable remote login with password altogether, but I want to make it so that my account is only accessible with key pair authentication (there are other users who wants to use ...
8
votes
3answers
169 views

Trap: can't su as root, can't change group to wheel, ssh as root prohibited

Is this a trap? I made these steps in FreeBSD 10: 1) ssh as root prohibited 2) logged as user 3) su as root 4) as root chsh changed name of user "user" to "luser" 5) exit from ...
8
votes
2answers
3k views

I Can't login as root with su command, but I can with SSH

How is it possible that I cannot log in as root by su root or su (I get incorrect password error), but I can log in by ssh root@localhost or ssh root@my_local_IP with the same password? I'm using ...
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
446 views

iPhone type login screen?

The person that introduced me to Fedora had somehow made his login screen so that instead of typing in a password he used the "connect the dots" password that's popular on phones. Eg On my ...
6
votes
3answers
9k views

ssh remote server on some port other than 22 without password

I am usually connecting to the remote server with ssh user@server.com -p 11000 and then giving the password each time for user. How should I avoid entering the password each time I connect ...
6
votes
3answers
316 views

login and su internals

I am trying to understand how user permissions work in Linux. The kernel boots and starts init as root, right? Init then runs startup scripts and runs getty (agetty), again as root. Agetty just reads ...
6
votes
4answers
1k 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
3answers
140 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
4answers
2k 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
2answers
14k views

How to telnet via proxy authentication?

I am behind a proxy server in my college. It uses a simple username and password authentication. And i connect to the proxy server to port 3128. now i want to telnet simply to say any website on the ...
5
votes
3answers
1k views

Permit root to login via ssh only with key-based authentication

I have some doubts about certain ssh server configurations on /etc/ssh/sshd_config. I want the next behavior: Public key authentication is the only way to authenticate as root (no password ...
5
votes
2answers
5k views

Not able to ssh in to remote machine using shell script in Crontab

Below is the script which i am trying to run, which runs without any issue for i in `seq 200 2100` do usr=(`ssh -t -t -o ConnectTimeout=60 machine$1 finger | tail -1 | awk '{print$1}'`) echo ...
5
votes
2answers
945 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
1answer
556 views

Custom PAM modules and security considerations

I am writing my own PAM module that will be part of an application that I am developing, but I'm not sure exactly where to put it. My module basically does network-level authentication (with other ...
5
votes
1answer
159 views

Apache Authorization for the Allowed Users?

I have read the answer to this question: http://stackoverflow.com/questions/4102763/apache-basic-authentication-except-for-those-allowed It helped me understand how to not authenticate some users ...
5
votes
1answer
151 views

Command line printing with a Samba printer requiring authentication

Is there a way to print to a Samba printer requiring authentication by providing the credentials on the command line (e.g., with lpr)? I managed to store the credentials in GNOME Keyring and when I ...
5
votes
2answers
114 views

PAM - required and sufficient control flag

I'm studying PAM, and I'm a bit clueless about the meaning of some combination of control flags. From the Red Hat documentation we have: *required failure of such a PAM will ultimately lead to the ...
5
votes
1answer
3k 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
1answer
88 views

2 Factor Authentication in SSH using public key and PAM

I'm trying to setup 2 Factor Authentication. I want the user to login successfully if: The public private/public key matches (authentication method: publickey) or the password is correct My pam ...
4
votes
2answers
244 views

Allow user1 to “su - user2” without password

I need to allow user martin to switch to user martin-test without password su - martin-test I think this can be configured in /etc/pam.d/su. There are already some lines in that file which can be ...
4
votes
1answer
842 views

Does the SFTP server accept passwords at all?

I'm trying to connect to a sftp server via sftp USERNAME@SERVERNAME. Whatever I do, I get "Permission denied (publickey)." Googling doesn't help as everybody recommends switching to key-based ...
4
votes
2answers
559 views

How to disable “Shake password dialog when authentication fails” of Gnome Screensaver?

Is there any way to disable the animation which occurs when attempting to unlock gnome Screensaver and failing? Currently the password dialog shakes back and forth and for some reason on some laptops, ...
4
votes
6answers
929 views

Identity Management with ActiveDirectory

What is the best, or most reliable, way to manage my Unix/Linux user accounts with ActiveDirectory? Or, is this even feasible?
4
votes
1answer
4k views

how do I configure my RHEL5 or RHEL6 system to use ldap for authentication?

I have root access to a RHEL6 system and I want to use the corporate ldap server where I work for user authentication. I ran authconfig-tui and checked [*] Use LDAP and left [*] Use Shadow ...
4
votes
1answer
14k views

Suddenly, I Can't login with correct password (greeter & tty)

This might be a duplicate of other password related questions but it's somehow eccentric. I have 3 accounts in my Ubuntu 12.10 system (one standard and two administrators). One of the administrator ...
4
votes
1answer
154 views

Easiest way to manage users for two machines

I'm administrating two ubuntu desktops and one debian server. There are abount ~20 active users on the desktops. A few (5-10) user accounts are added each year and about the same amount become ...
4
votes
1answer
858 views

Program to keep track number of login attempts

Is there any way to keep track of number of attempts made by a user to login into his system?
4
votes
0answers
29 views

How can I determine which SSH keyfile was used to authenticate a login?

We have a hosted CentOS 6.5 server in which we have a single user account. That account has been configured to use SSH keyfile authentication for the users who need to access it. I would like to be ...
4
votes
2answers
1k views

Lenovo T440s Fingerprint reader in Fedora 20

I just got my new Lenovo T440s and installed Fedora 20 with Gnome 3 on it. Everything runs smoothly, except for the fingerprint reader. Its got a Validity VFS5011 (138a:0017) device which is not yet ...
4
votes
1answer
279 views

Configuring Apache to Require a Client Certificate

I want to implement mutual authentication (two - way ) with apache web server. References : 1.Failed to sign CSR with the CA root key 2.Firefox error message when adding client certificate ...
4
votes
1answer
1k views

Git-SVN Not Allowing Me to Authenticate

Git 1.7.9.1 on Arch Linux: git svn init -s https://app.svn.beanstalk.com/repo Initialized empty Git repository in /path/to/repo/.git/ Authentication realm: ...
3
votes
2answers
119 views

SSH when to use public key and password?

I think I understand the difference between Public Key authentication and Password. But how do I decide which one to use and which one is most secure in what situation? Can anybody give me some real ...
3
votes
3answers
200 views

Is there way to stop random software packages from remotely transferring your files?

I am running a bitcoin client on my archlinux computer. If somebody can get ahold of the wallet.dat file, located in the ~/.bitcoin/ directory they can steal my coins. I have minimal software ...
3
votes
2answers
334 views

How do you automatically elevate an automatic task to root privileges or is there an alternative approach?

I'm trying to write, in essence, an automatic deployment script for use by our development team and I know I can set up SSH to use keys so that I can automatically authenticate via key instead of ...
3
votes
1answer
4k views

Can't login as root even after resetting the password

We're running a small Centos 5 server in a virtual machine for a class assignment. For reasons unknown, starting about a week ago a number of services started failing. When we tried to investigate we ...
3
votes
1answer
11k views

How to enable remote login?

Currently I can only login to my remote linux via the "ubuntu" user account, without a password (via SSH authentication). I have another user configured on the machine, and if I try to login with its ...
3
votes
2answers
6k views

How to configure for an Authenticating Proxy Server

My work proxy server requires authentication with the Microsoft AD domain user credentials. Everybody knows how it works: If you log in on a Windows workstation, your "Internet Explorer" browser based ...
3
votes
1answer
182 views

How are loaded SSH keys referenced by name?

I'm using chef's knife ec2 tool which requires the name of a loaded SSH key (that was created in the Amazon EC2 control panel) It seems strange to me that it uses a name to reference the keypair - ...
3
votes
1answer
187 views

mod_authnz_ldap bind as authenticating user instead of anonymously

I'm attempting to move as close to single credential as possible. We have a web application that has a fairly limited set of available authentication mechanisms but will (luckily) allow admins to tell ...
3
votes
1answer
19 views

How to set an expired authentication in Apache?

Using a simple virtual host, I've to set a timeout after X minutes (same of set an expired authentication) to force the user to re-insert its credentials. [...] <Directory /home/user1/> ...
3
votes
1answer
666 views

Firefox error message when adding client certificate signed by CA

I'm getting this message when I'm trying to add a certificate to Firefox's "your certificate tab". I generated and signed it before by a server which also is a CA. Failed to decode the file. ...
3
votes
1answer
410 views

Multiple PCs network centralized system authentication

(I couldn't really choose an accurate title as I don't know exactly what the feature I'm looking for is called. Sorry about that. I hope that the following lines may clear this aspect.) I own a dozen ...
3
votes
1answer
396 views

What's the best way to install a system-wide certificate from a website?

I want to use the Cisco Easy VPN to connect to the OpSource cloud machines. When I open the app, it directly shows a certificate error message, I suspect that the certificate is not trusted from their ...