Questions regarding password-based authentication and password management

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3
votes
3answers
7k 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 ...
30
votes
2answers
9k 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 ...
11
votes
6answers
1k 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 ...
11
votes
3answers
280 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 ...
2
votes
1answer
532 views

How to enter/choose session after logout without password in (Linux Mint) Xfce?

I have Linux Mint 14 Xfce (4.10) and have also installed LXDE desktop, so I can choose between these sessions if I want. Normally I would set one as default and at startup I am not asked for ...
4
votes
2answers
655 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)
21
votes
3answers
5k 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 ...
9
votes
4answers
7k 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.) ...
8
votes
2answers
500 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?
4
votes
2answers
6k 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 ...
6
votes
2answers
2k 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 ...
3
votes
1answer
555 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 ( ) ...
2
votes
3answers
366 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 ...
2
votes
1answer
589 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 ...