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Questions tagged [shadow]

Shadow passwords is a security feature commonly used on Unix and Linux systems.

Unix and Linux systems store passwords as salted hash values. Historically these were stored in /etc/passwd along with other user information. For security reasons most systems have since moved the passwords to /etc/shadow such that only privileged programs have access to the hashed passwords. Some systems are using a group named shadow to manage access to this file.

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Diskless login with Linux/OpenSolaris

Is it possible to enable a Linux or OpenSolaris based server to process standard unix login requests without spinning up the hard drive holding the root partition? I have a Nexenta-based (1) server that uses a very old 40GB PATA drive for the root…
HonoredMule
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updating shadow file in a KVM guest in a mounted system

I have a KVM guest that I need to reset the password. If I use 'virsh console' to access the guest account, I'm able to update the shadow file with a new hash line like…
Purres
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What's !* in the password field in /etc/shadow?

Looking into my /etc/shadow file of a fairly new box today (running Arch), I see some passwords as * (disabled) but some others as !*, !! and as !. Presumably that means "disabled", too, but why is the value different? Is there some convention that…
Johannes Ernst
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Why shouldn't LDAP support inequality searches on shadowExpire?

When I try to search my OpenLDAP 2.4.42 server for (shadowExpire<=18074), I get no results. However, a search for (shadowExpire=12671) yields several results. My ultimate goal is to periodically regenerate a Postfix map for check_recipient_access…
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Linux custom NSS module, `_nss_SERVICE_getspnam_r` is called but `_nss_SERVICE_getpwnam_r` is not

I'm creating a custom NSS module. I managed to make it work on my local Redhat 7.3 box, configured nsswitch.conf correctly passwd: files SERVICE shadow: files SERVICE and confirmed that both _nss_SERVICE_getpwnam_r and _nss_SERVICE_getspnam_r are…
terencezl
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Can't edit files /etc/passwd and /etc/shadow

I have some issues with files /etc/passwd and /etc/shadow. Both of them are without permissions: ---------- 1 root root 1357 Aug 5 11:30 passwd ---------- 1 root shadow 1175 Aug 5 11:30 shadow And i don't know how this happened or why.…
Martin Sudolsky
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Change password hashing algorithm for SuSE users from blowfish to MD5

I have a network of roughly 1000 SuSE machines with 20-200 users on each. The password hashing algorithm used is the default i.e. blowfish. In order to check, whether a user has used a dictionary word as the password, have written a small utility…
Amit Kumar
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RHEL not accepting any passwords

I have RHEL 5 on virtual machine installed. I was creating the new user by making entry in /etc/passwd. I deleted the /etc/shadow file and used pwconv command to make new shadow file. Now when i restarted the system , it is not accepting any…
John
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Restore passwd for root on a server

      I have a DVR server with linux embeded. It has some telnet functions but i don't have the password for it (the chinese manufacturer refuses to give me the password). I did get a upgrade folder from them and found a passwd file…
s.mihai
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Strange record in /etc/shadow after useradd -p and crypt function in bash script

Ubuntu 20.04 LTS. There is a simple bash script to add a new user via command line in interactive mode: #!/bin/bash # Script to add a user to Linux system if [ "$(id -u)" -eq 0 ]; then read -p "Enter username : " username read -s -p "Enter…
Skuld
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How to create a user and give it read permission to /etc/shadow file?

I would like to give my web server user (nginx) read access to the /etc/shadow file and I would like to confirm the steps that I am taking to do this. The system I am using is a CentOS 7. First I created a group called shadow: groupadd shadow Then…
Nebek
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can't reset password from centos

I lost the root password. So I modified /etc/shadow and also changed '/etc/inittab' file to access single user mode. But both didn't work. It asked me for a password that I don't have. Why updating the two files doesn't work? I mount the file…
Purres
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manually editing shadow file on disk from raid1 array

At work we have a machine to which root password has been lost. I have pulled out the disk and mounted it to another computer. Now I think the next step should be editing root password in the shadow file. But the disk I have pulled out is actually…
clime
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Understanding linux /etc/shadow file structure (Linux)

Consider the following line taken from /etc/shadow file: root:$1$NFEf74q.$bmukkxAq9dOMJINgEtP7u0:15258:0::::: From this I understand that the hashing algorithm is md5 ($1) and starting from third $ sign is the hashed password consisting of 22…
astralmaster
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