Questions tagged [password]

Questions regarding password-based authentication and password management

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29
votes
10answers
196k views

Shell Script for logging into a ssh server

I tried writing a shell script which can do automatic login into a ssh server using password which is mentioned in the script. I have written the following code: set timeout 30 /usr/bin/ssh -p 8484 ...
88
votes
3answers
29k 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 ...
10
votes
1answer
1k views

How to change the forgotten root password?

I forgot my root password...actually I think I know what it is because it is the same password I have for pretty much everything but in the Terminal in tell me "Sorry, try again." Is there a way to ...
81
votes
8answers
213k views

How to create SHA512 password hashes on command line

In Linux I can create a SHA1 password hash using sha1pass mypassword. Is there a similar command line tool which lets me create sha512 hashes? Same question for Bcrypt and PBKDF2.
39
votes
3answers
235k views

How can we change root password?

If we don't know the root password and don't have root access to the machine, how can we change the root password?
67
votes
3answers
5k views

How does curl protect a password from appearing in ps output?

I noticed some time ago that usernames and passwords given to curl as command line arguments don't appear in ps output (although of course they may appear in your bash history). They likewise don't ...
29
votes
2answers
49k views

/etc/shadow : how to generate $6$ 's encrypted password? [duplicate]

In /etc/shadow file there are encrypted password. Encrypted password is no longer crypt(3) or md5 "type 1" format. (according to this previous answer) Now I have a $6$somesalt$...
361
votes
8answers
333k views

How to force ssh client to use only password auth?

If I use pubkey auth from e.g.: an Ubuntu 11.04 how can I set the ssh client to use only password auth to a server? (just needed because of testing passwords on a server, where I default log in with ...
104
votes
8answers
225k views

Manually generate password for /etc/shadow

I need to manually edit /etc/shadow to change the root password inside of a virtual machine image. Is there a command-line tool that takes a password and generates an /etc/shadow compatible password ...
17
votes
3answers
29k views

How to pass password to mysql command line

I have MySQL password saved on a file foo.php, for example P455w0rd, when I try to use it: $ cat foo.php | grep '$dbpwd=' | cut -d '"' -f 2 | mysql -U root -p mydb -h friendserver Enter password: (...
17
votes
3answers
24k views

Reading passwords without showing on screen in Bash Scripts

How to read passwords in bash scripts in a way like tools which are not showing it on terminal ? (Changing font to black on black might be tricky by easy to copy&paste - so it's not solution)
9
votes
3answers
3k views

Securely feeding a program with a password

After understanding the problem with using a password in the command line, I need to find a way of feeding a program with a password without it being a problem (without the password being recorded ...
86
votes
7answers
172k 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 ...
3
votes
4answers
4k views

passing passwords to a script

I want to scp a file to a remote host, and from there, run a command on the file, and exit the remote session. If I write a usual script, call scp and then ssh, I am prompted to enter two passwords. ...
27
votes
4answers
127k views

How to make user passwords shown as a clear text in Linux?

We know that users' passwords are saved in /etc/passwd, but in an encrypted way, so even the root can't see them: jane:x:501:501::/home/jane:/bin/bash fred:x:502:502::/home/fred:/bin/bash As shown ...
22
votes
8answers
74k views

Hiding Password in Shell Scripts

How can I hide a password in shell scripts? There are a number of scripts that are accessing database. If we open the script others also aware the username and password. So if anyone knows how to hide ...
10
votes
4answers
26k 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 ...
17
votes
1answer
13k views

In /etc/group what is the meaning of the second field?

A sample /etc/group file contains the following entries: root:*:0: adm:!:4:logcheck antoine:x:1000: The man pages I've read (Debian & OSX) says the second field is to store a group password. As ...
5
votes
1answer
2k 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 ...
7
votes
1answer
953 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 ...
3
votes
1answer
3k views

wpa_supplicant store password as hash (WPA-EAP with phase2=“auth=PAP”)

Is there a way to store my password in /etc/wpa_supplicant/wpa_supplicant.conf as some hash instead of plaintext? By "password" I refer here to the password used for phase2 authentification. I do not ...
200
votes
21answers
172k views

How to generate a random string?

I would like to generate a random string (e.g. passwords, user names, etc.). It should be possible to specify the needed length (e.g. 13 chars). What tools can I use? (For security and privacy ...
50
votes
4answers
77k 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 ...
22
votes
2answers
28k views

Simplest way to password protect a directory and its contents without having to create new files?

I would like to password protect or encrypt a directory and all the files within it (for the whole directory tree below it). I do not want to bother the whole home directory, I want a specific ...
38
votes
3answers
12k views

Why is the password I entered not visible?

Below is an image of the process I took to create a user on bash in Linux. I understand that the password shouldn't be displayed for security purposes, but what I mean is, why do asterisks (or the ...
52
votes
5answers
46k views

SSH keeps skipping my pubkey and asking for a password

Every time I ssh onto my remote server, I need to provide the password. I copied my public key (id_dsa.pub) to the remote server using: ssh-copy-id -i id_dsa.pub user@server I checked it was ...
22
votes
2answers
26k views

Hiding passwords in wpa_supplicant.conf with WPA-EAP and MSCHAP-v2

My wpa_supplicant.conf looks like this: network={ ssid="Some name" scan_ssid=1 key_mgmt=WPA-EAP eap=PEAP identity="my-user-id" password="(clear text password here)" ca_cert="/usr/share/...
21
votes
5answers
93k 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.) ...
33
votes
3answers
5k views

Why shouldn't someone use passwords in the command line?

Why do people fear writing passwords in the command line? The history file is located in ~/.history, so it's available only to the user who executed the commands (and root).
17
votes
2answers
2k views

Ask for a password in POSIX-compliant shell?

When I want to ask for a password in a bash script, I do that : read -s ...but when I run bash in POSIX mode, with sh, the -s option is rejected: $ read -s sh: 1: read: Illegal option -s How do I ...
42
votes
4answers
7k views

Solaris let me in with different password with the same 8 first characters

I don't know if this is normal, but the thing is, let's say I have a Solaris user called gloaiza and its password is password2getin I'm logging into the server with PuTTY, I just put 192.168.224.100 ...
11
votes
2answers
94k views

How to lock users after 5 unsuccessful login tries?

How to lock users after 5 unsuccessful login tries? I gathered a few distributions/versions to how to do it, but I can't test it. RHEL4: by adding the: auth required /lib/security/$ISA/...
11
votes
1answer
19k views

Why 'mkpasswd -m sha-512' produce different result every time it is called?

I am using this function to create a password in the shadow file $ mkpasswd -m sha-512 password $6$o50n4EfNOBzfs$K5l5AcOI5e0I9n2df0LmR11OLSPKSVM6AGBOnWVfDDfMubb46MrAj0zehdLNEoYzD2fj5q4XUdDwexj/dWLHy/ ...
9
votes
2answers
61k views

can't ssh into remote host with root, password incorrect

I have a remote host, previously I can ssh into it with root and password ssh root@remote_host or I ssh into it first using a regular user account ssh esolve@remote_host and then su root and input ...
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 ...
12
votes
6answers
39k 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 /usr/bin/...
11
votes
2answers
10k views

Change Password Programmatically

In the current version of Raspian, I know it is possible to change the password of the current logged in user from the command line like so: sudo passwd which will then prompt the user to enter a ...
5
votes
2answers
9k views

What is the difference between these two ways of reseting the root password?

I know several ways to reset root user's password, but want to know which is the best and why it is. For example: A method: Grub > 'e' init=/bin/sh (Remove rhgb and quiet tags if necessary) > ctrl+x /...
3
votes
2answers
5k views

Resetting password of another Linux

I have an external hdd partitioned into two. One of the partitions has Linux (Ubuntu) installed on it (bootable). The thing is I have forgotten the password of it's user (single user). How can I ...
23
votes
2answers
8k views

How long is the password for executing a command with sudo cached?

If I run a command which requires root privileges with sudo, I will be asked to enter the current user's password. After that for a while, if I execute the same sort of commands with sudo, I won't be ...
16
votes
4answers
642 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 ...
15
votes
3answers
40k 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 be able ...
7
votes
1answer
883 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?
12
votes
1answer
14k views

Difference between passwd and passwd- file [duplicate]

Possible Duplicate: Who creates /etc/{group,gshadow,passwd,shadow}-? I have a strange passwd- file in /etc, notice the trailing dash: root@ubuntu:~# ls /etc/passw* /etc/passwd /etc/passwd- ...
11
votes
4answers
18k views

Why should you NEVER edit the /etc/shadow file directly?

In another answer here on UNIX & Linux Stack Exchange Michael D Parker wrote, in response to someone saying that doing so was "safe", that:Usually you should NEVER edit the /etc/shadow file ...
3
votes
1answer
4k views

Can I automate mounting a cifs share without storing my password in plaintext?

I currently use a script which contains commands along the lines of sudo /sbin/mount.cifs $SERVER_SHARE $MOUNT -o username=$DOMAIN_$USER,uid=$USER,gid=$USER,file_mode=0664,dir_mode=0775 to mount my ...
2
votes
1answer
888 views

upload and dowload the files from server without giving password

I want to download the file from sever by using cron job, so I need to use scp command without giving password by keyword. How do I do so?
2
votes
4answers
79k 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 ...
-1
votes
5answers
4k views

Use a password in shell-script

I want to create a cron script to interact with mysql, for example #!/bin/bash mysql -uroot -p echo root echo "CREATE DATABASE example" But it doesn't work, it only prompts: Enter password: and ...
6
votes
3answers
4k 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 doesn't show anything as Password: I want to it to show at least some asterisks as the placeholder for the password ...