Questions regarding password-based authentication and password management

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5
votes
3answers
705 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?
0
votes
1answer
108 views

How to change password of an ssh identity file

Can I, and in that case how can I, change the password of an SSH identity file without having to generate a new key and setting up it all over again?
0
votes
1answer
32 views

How to see the password in rhel6 [duplicate]

How to see the password what we are entering in RHEL6. If not how to see at least the entering password in some special characters.
1
vote
1answer
183 views

Why root is not constrained by pam

I have the following settings in file /etc/pam.d/common-password. password requisite pam_cracklib.so retry=3 lcredit=-1 ucredit=-1 dcredit=-1 password [success=1 ...
1
vote
1answer
101 views

How to format password using SCP

I'm currently writing a Script to upload files to my server via SCP. I have the following line: sshpass -p password!% scp -P 1234 ./test.text user@mydyndns:~/test.txt But everytime I try that I ...
2
votes
1answer
153 views

What does **___________ mean in /etc/shadow?

When I look at /etc/shadow I see several entries that look like this: username:**___________::::::: What does the "**___________" mean? That is where I should see the password hash.
1
vote
2answers
96 views

What could be causing a delay between running passwd and being able to login with that password?

I have a RHEL 6.6 Server that I am seeing odd behavior with. When I change a password using the passwd command, the /etc/passwd file gets updated without issue (confirmed with timestamp check). ...
0
votes
1answer
596 views

CentOS 7 - while installing i set disk encrypted with password, but on reboot always it asking password

While installing CentOS 7, i put password for disk encrypt. Now while working remotely on that machine and doing reboot it always ask password to be inserted on-site. Is this normal? or there is a ...
5
votes
4answers
720 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 ...
2
votes
1answer
187 views

How to safely transmit a password over SSH for a remote command to use

On the local server, I have a program that stores the password in the predefined environment variable (SPECIAL_PASSWORD). On the remote server I have a program that reads and uses a password from a ...
2
votes
1answer
322 views

Edit samba user password hash/digest without knowing the password

I am maintaining a samba server for an office environment. So far, whenever there had to be a new user, I called the person over and let him type in his samba password on my console, after I typed ...
0
votes
1answer
40 views

dhcpd restart command asks for password from command line but not from a script?

I have a script that runs and will ssh into another server to restart its dhcpd. In the script, the command literally is: sudo ssh -n $SERVER /sbin/service dhcpd restart This works fine when the ...
5
votes
1answer
251 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 ...
1
vote
2answers
1k 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: (...
1
vote
2answers
149 views

Script samba password but securely

I want to script the addition on a samba user and the password. I have seen solutions similar to the one here Piping password to smbpasswd echo -ne "$PASS\n$PASS\n" | smbpasswd -a -s $LOGIN but ...
0
votes
1answer
86 views

How can I get a log of all incorrectly entered passwords in linux?

How can I get a list of all incorrect passwords used whenever someone tried to log in. And how can this be generalized to all types of password fields in linux? As it mentioned by K1773R, yes it's a ...
1
vote
2answers
518 views

Script to read line by line from a file pipe that to another command and output to another file

I've got this weird old app that I'm trying to support and it stores the passwords in plain text and I'd like to hash them. I'd really like to have an input file in csv with a username,password for ...
1
vote
1answer
445 views

Set a password on Damn Small Linux

I'm running Damn Small Linux. When you open the command prompt, you are automatically logged in as the default user called dsl and granted root privileges (with sudo). How can I set a password for the ...
1
vote
4answers
1k views

How to “cat /etc/shadow” on an HMC?

hscroot@hmcserver:~> grep root /etc/group root:x:0:hscroot,ccfw hscroot@hmcserver:~> hscroot@hmcserver:~> ls -la /etc/shadow -r-------- 1 root shadow 5252 2015-05-06 19:36 /etc/shadow ...
1
vote
1answer
194 views

passwd does not work after change CRYPT_DEFAULT

I want to change algorithm for password encryption in Solaris 10 server. When I change CRYPT_DEFAULT option from __unix __ to 6, I can not change my old password with passwd command and I get ...
4
votes
2answers
180 views

how to prevent a buffer from swap

this question is specific to Unix and Linux. but it is programming and security, too. my program will get a clear password or decryption key by one of a few ways (decrypting a password file, asking ...
0
votes
2answers
841 views

How to make the script automated to take password on its own?

I have a script that is doing sftp some files from one server to another, like inside the script script.ksh I have the below lines; sftp user@ip_address << EOF cd path put file1 bye EOF When ...
0
votes
0answers
96 views

What is the user and password for Sabayon Linux?

I am currently unable to use my computer because I can not login. I've burned thrice the daily minimal-dev Sabayon Linux ISO onto the same USB flash device. Each time, the login screen asks for login ...
1
vote
0answers
343 views

logging wrong passwords in /var/log/auth.log

/var/log/auth.log logs (among other things) failed login attempts to my debian linux. I was wandering if it is possible to ask it to log the password that was used in the failed attempt. This is ...
2
votes
1answer
287 views

GNU Screen - any way to remove password when detached?

Protecting a GNU screen session with a password is good security. However, how does one remove the password if you need to share a session with a colleague? I tried the following to clear it and got ...
-3
votes
2answers
153 views

A little help passwd status on linux

On a linux distro user mino report this passwd status passw -S mino mino P 04/21/2015 0 90 15 -1 P=passwd ok 04/21/2015 = date creation 0 min pass? 90 max pass valid 15 = ? -1 = ? Thanks
2
votes
2answers
1k 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 ...
1
vote
1answer
235 views

LDAP Force Password Change Through HTTPS

We have a "master" server running Suse Enterprise with LDAP that controls user's access to our systems. We want to implement a 90 day expiration policy, but the issue is that most of our servers are ...
5
votes
2answers
2k 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 ...
1
vote
1answer
117 views

Configuring Exim on Debian to authenticate using only a password?

I am attempting to configure Exim in such a way that clients who wish to relay email through the server must supply a single passphrase. The file /etc/exim4/conf.d/auth/30_exim4-config_examples ...
0
votes
2answers
139 views

SSH authenticity couldn't be established

Last night I SSH'ed to different systems.... one system/SSH reported that the "authenticity of HOSTNAME couldn't be established......." and it asks if I want to continue or something, I didn't and ...
3
votes
1answer
3k views

Policy in /etc/pam.d/password-auth is not being enforced

I've updated login.defs and password-auth to include a minimum length on passwords (12), but the minlen is not being enforced when I attempt to change a user's password with passwd. None of the ...
0
votes
0answers
118 views

shell script prompting for password but not taking it while doing tar

In my shell script, I have following lines: function tarIt() { FILE_OWNER=$1 TAR_FILE_NAME=$2 FILE_NAME=$3 su - $FILE_OWNER -c "tar -czf $TAR_FILE_NAME $FILE_NAME 2>&1" if [ ${?} -...
2
votes
2answers
396 views

How can I store an encrypted rdesktop password for easier sign-in?

I am using rdesktop on a Fedora laptop to connect to Windows computers at work. To make it easier, I've made an alias in my .bashrc: alias companyremote='rdesktop -u USER -p - -g 1920x1040 -K' So I ...
4
votes
1answer
844 views

How can I decrypt my encrypted /home partition?

A year ago I installed Linux Mint 17 on my laptop. I partitioned the HDD and separated the system (/ mount point) and the data (/home mount point). I chose to encrypt the whole /home using the basic ...
6
votes
3answers
5k views

How to unlock account for public key ssh authorization, but not for password authorization?

The ssh won't let me login, because account is locked. I want to unlock the user on my server for public key authorization over ssh, but do not enable password-ed login. I've tried: # passwd -u ...
4
votes
1answer
280 views

Change the root password of a Linux image

I'm building a jessie build of Debian. Passwords are saved in /etc/shadow in the build tree, but they are salted obviously so I cannot change it just by editing the file. If this was my installed ...
1
vote
1answer
213 views

How do I log in to Mint when I've forgotten my password?

I'm brand new to Linux. I bought a laptop with Linux Mint 17.1 installed on it, but I can't remember the log in password. Is there a way of disabling it?
0
votes
2answers
81 views

/etc/passwd shortest password

I need to put one character inside the password file so that nobody can notice. I thought that if I was able to put the password as plain text and put something like a space nobody would ever find out....
2
votes
1answer
699 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
109 views

How to Find the number of password entries that are on the server? in unix [closed]

Find the number of password entries that are on the server? in UNIX
-2
votes
3answers
170 views

What is “-l” option do to the passwd command? [duplicate]

I have seen people use passwd -l "$USERNAME" , But the linux man page does not explain what the -l option is for. What does it do ?
1
vote
4answers
131 views

How can I update a password without entering the password twice?

I effectively have a sticky keyboard (host machine to RDP to vCenter to virtual console), but need to update the password of a VM I am building. Using the rescue environment CentOS media offers, I ...
2
votes
1answer
45 views

Where do my keypresses go ?

Scenario (Ubuntu 14.04.2) : I wake Ubuntu from suspend. I know (from past experience) that it only takes 2 or 3 seconds for the lock screen to become available. My monitor, however, takes longer - ...
4
votes
2answers
2k 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 ...
1
vote
1answer
655 views

smd5 - generate by unix tool or perl

I have problem on Unix, have to create a lot of passwords in smd5 but don't know how to generate smd5 passwords using some unix tool or perl in a form: {smd5}DoZgZ.OE$vSg4ZH7Bpy0BCdXNzBj001 I have ...
2
votes
0answers
224 views

Persistent SSH port forward without public keys

Problem I haven't found a solution to run an SSH port forward in a reliable and persistent fashion, when the server you are connecting to does not support public-key authentication. Question What ...
3
votes
1answer
125 views

How to blacklist common passwords on UNIX systems?

If we have a file on a server (Linux, AIX, etc) that contains the common passwords, how can we filter passwords based on this?
1
vote
0answers
468 views

md5 password hash

I'm looking to create a md5 hash to use in /etc/shadow. Someone suggested using grub-crypt. Every time I put the same password in I get a different hash. [root@endpoint ~]# grub-crypt --md5 Password: ...
2
votes
4answers
98 views

can a super user steal passwords from other users with keylogging?

First, before I get answers containing information that I already know, yes, I'm aware that the superuser can reset passwords, and yes, I know that the superuser can log in as other users without ...