Questions tagged [shadow]

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1answer
64 views

Linux - create user with no password (login without password prompt)

I found many articles mentioning that user has no password after using passwd -d. While on some of my systems it indeed works (I can su from unprivileged accounts to them without giving password) on ...
1
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0answers
30 views

Single digit in /etc/shadow file Solaris for password hash

In the /etc/shadow file, I should expect to see like below:- loginID:passwordHash:...... In the case of Solaris, passwordHash should be a 13-character hash value. What does it mean then, if on my ...
1
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1answer
58 views

sg: not found - Alpine Linux

I am trying to execute a command with a specific user group as described in the linked question (How to run a process with a specific group?) on Alpine Linux, but the system says "not found" ~/work $ ...
3
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1answer
60 views

Why does /etc/shadow uses user name instead of uid?

/etc/shadow contains the username, but not the uid. Is there a specific reason, why a char * field was chosen over an int? For direct username->password check this might be quicker, but for ...
1
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0answers
55 views

/etc/shadow is empty, yet I am prompted for password

I have a board (Pine64) on which I run my custom-built linux distribution (using buildroot). I configure root to have no password, and the resulting /etc/shadow file looks like this: root:::::::: ...
4
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1answer
260 views

Disable password on linux user with command

Based on /etc/shadow(5) documentation on the second (password) field: encrypted password If the password field contains some string that is not a valid result of crypt(3), for instance ! or *...
5
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1answer
760 views

How to know if password in /etc/shadow is hashed with SHA or MD?

I want to know my /etc/shadow password hash if its SHA or MD or something else. From what I read, it is related to the $ sign, but I don't have any dollar signs. Im using Ubuntu 16 Example: user:0....
0
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1answer
49 views

Screen Lock Checks password file but not Active Directory

We have a Linux system running Centos 7 and have an issue with the screen lock. We have a multi-user environment where each user has their own account. The authentication is using our university ...
37
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3answers
6k views

When did Unix stop storing passwords in clear text?

When did Unix move away from storing clear text passwords in passwd? Also, when was the shadow file introduced?
0
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0answers
8 views

back up file for shadow

My back up file for shadow is different to my shadow file in one line, in the backup the last two characters is "::" where as in the shadow file itself it has an additional character, the last three ...
-1
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2answers
389 views

What is mean “x” in second field of /etc/shadow file [duplicate]

I have content in shadow file: root:!:17777:::::: bin:x:14871:::::: daemon:x:14871:::::: mail:x:14871:::::: ftp:x:14871:::::: http:x:14871:::::: dbus:x:14871:::::: nobody:x:14871:::::: systemd-...
1
vote
1answer
53 views

How can the shadows around windows be removed from Mate with Lightdm?

There is a shadow around each window in Mate. If it matters I run Lightdm. How can the shadows be completely disabled for all windows regardless of the application?
2
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1answer
79 views

How to upgrade shadow package in Debian

I have been told one of my Docker images has "Docker security issue CVE-2017-12424", says one of its package shadow version is "1:4.4-4.1". And I need to upgrade. But I can only see version 1:4.4-4.1 ...
3
votes
1answer
353 views

Why is +::0:0::: not supposed to be found in /etc/passwd?

I was reading the BSI Security Guidelines (GERMAN), on NIS and it explicitly mentioned that one should prevent the entry +::0:0::: from occuring in the /etc/passwd file of the NIS server. From my ...
2
votes
1answer
476 views

lightdm does not show users which have no shadow password

I have switched my virtual machine, to use a ldap server for authentication with sssd. I assumed with this setup I will not need to use local passwords anymore, as i can login with ldap authentication....
3
votes
1answer
126 views

Blank root password disabled in modern distros?

Having read this: https://stackoverflow.com/questions/11700690/how-do-i-completely-remove-root-password I was under the impression that a blank root password, as in modifying the /etc/shadow file for ...
0
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0answers
109 views

case-preserving linux usernames and hostnames

Is there a way to set pam library to do case-preserving username validation? Is there a way to set useradd command to accept and preserve the case of usernames? I know usernames and URLs are not OS ...
-6
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1answer
83 views

Crack a user password [closed]

I need to crack a user password at /etc/shadow which is hashed in sha512 with specific known salt
-1
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3answers
2k views

what is the difference between /etc/shadow and /etc/passwd [closed]

What is the major difference between /etc/shadow and /etc/passwd In /etc/shadow we have the same data as in /etc/passwd.
0
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1answer
92 views

ffcast and compton - a shadowy problem

So I have compton, a composite manager that I use to make things look prettier, mostly to add shadows to windows, and make things transparent. I also have ffcast, which I currently am using to make ...
2
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2answers
1k views

How to manage /etc/passwd file

Let's say I want to keep the /etc/passwd file divided into system users like admin, wheel, root etc., and by actual users all at the end. How do I do that? By creating subdirectories?
0
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1answer
136 views

useradd command truncates the password mentioned with -p option

Command is as below, which is executed on wind river linux manchine. useradd vpatest -c Pav -g guest -G log -s /data/bin/cli.sh -p $6$cem^CM38$4YdQAPgu8EXNG3ecurYk4eN1sIiYNauBdHFRJew3l/...
0
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0answers
24 views

Hyphen Suffix on file name [duplicate]

I decided to randomly take a look at my /etc directory, and I saw some entries like this: passwd passwd- shadow shadow- subgid subgid- I know they are hyphens (-) and not tildes (~). What are the ...
4
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1answer
3k views

When I copy /etc/shadow to another system, is it possible to login with the according passwords?

I am asking, because I generated a live CD using the hash from an existing /etc/shadow, assuming I will then be able to login with the corresponding password, but apparently login fails.
0
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1answer
1k views

Change Shadow Password

I am looking for a sed command to change the line: userA:$6$lhkjhl$sdlfhlmLMHQSDFM374FGSDFkjfh/7mD/354dshkKHQSkljhsd.sdmfjlk57HJ/:95170:::::: to userA:$6$sLdkjf$576sdKUKJGKmlk565oiuljkljpi/9Fg/...
4
votes
1answer
284 views

How Linux can compare old and new password?

I know that on Linux (at least debian) every password are hashed and stored in /etc/shadow. However thanks to the libpam-cracklib you can add some rules on passwords. For instance in /etc/pam.d/...
1
vote
1answer
422 views

How is PAM checking the user password in unprivileged processes?

PAM manages to check the user password, when called from unprivileged screen-lockers. E.g.: Password for GNU screen lockscreen command? https://github.com/google/xsecurelock I can't find any SUID-...
1
vote
1answer
49 views

Unable to recover lost login

I'm running Bananian linux on my Banana Pro recently I changed some config settings but quit it with ctrl + c without finishing editing all the config settings. After restart I am unable to login with ...
2
votes
1answer
876 views

What should be in the /etc/shadow file if I want my root account to be disabled?

On one of my machines it's root::somenumber[...]::: with somenumber[...] being the same as for my actual account (after what appears to be the encrypted passphrase) and the "logcheck" account (after :*...
2
votes
1answer
918 views

How to set password for a user using hash in /etc/shadow on Solaris

As part of a new build, I am tasked with creating user accounts on new Solaris server. I have to use the user accounts in an existing Linux server, and set the same password for each user on the ...
0
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1answer
446 views

Linux determines a user's first time login [closed]

I am working with an embedded Linux system not related to any standard Linux distro like ubuntu or centos. The system utilizes many standard FOSS packages like systemd, busybox, shadow, etc.. The user ...
-3
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1answer
161 views

The second field in /etc/shadow shows “!*” for user “bin” , “uucp” and few other service accounts as well. Can anyome explain the reason for !*? [duplicate]

The second field in /etc/shadow shows "!" for user "bin" , "uucp" and few other service accounts as well. Can anyone explain the reason for "!" ?
5
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0answers
3k views

getent shadow shows password hashes for some users

If I execute sudo getent shadow I see password hashes for all the local users who have them. For most of the LDAP accounts I only see * in the password field. However, for a few LDAP users, I see ...
3
votes
2answers
6k views

permissions on /etc/shadow

I am using Red Hat Enterprise Linux and here are the details: uname -a 3.10.0-327.22.2.e17.x86_64 When I check permissions on the shadow file I see the following: ls -l /etc/shadow ----------. 1 ...
84
votes
3answers
7k views

What is the 6th character of the password hash on Linux, and why is it often a slash?

On Linux, what is the sixth character of the password hash stored in /etc/shadow? On my puppy style linux box, if I try to generate 100 random passwords using shuf and /dev/urandom, then the sixth ...
1
vote
1answer
215 views

users resource in Puppet not updating /etc/shadow

I have written a manifests using users resource as shown below node 'node2.example.com','node3.example.com'{ user { 'ash': ensure => 'present', managehome => 'true', comment => '...
0
votes
3answers
428 views

How to set password expiration to infinite in shadow file?

I was reading more about how passwords are stored on linux and came across the number of days until password must be changed. The article I was reading says The number of days after which password ...
40
votes
2answers
48k views

Difference between ! vs !! vs * in /etc/shadow

The second field in the Linux /etc/shadow file represents a password. However, what we have seen is that: Some of the password fields may have a single exclamation <account>:!:..... Some of ...
1
vote
1answer
318 views

Managing(adding/deleting,etc) users in a squashfs(RO file system) with a small R/W partition

I'm using squashfs as the file system on a board which is RO, along with a small jffs2 partition which is R/W. The files corresponding to user management, i.e /etc/passwd, /etc/group & /etc/shadow ...
4
votes
1answer
10k views

Using hashed password for adduser function in Linux

Sorry, I´m novice in Linux and I am looking for information, how to create new user account in Debian with pre-defined encrypted password. I have a function in bash, that if new user´s id´s are not ...
1
vote
2answers
308 views

How to bulk add disabled-password users?

Doing: # newusers username::1002:1002::/home/username:/bin/bash ^D No password supplied No password supplied No password supplied newusers: (user username) pam_chauthtok() failed, error: ...
6
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3answers
2k 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?
2
votes
1answer
485 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.
2
votes
0answers
284 views

Is it possible to register “virtual” user/group IDs in a Linux system?

Is there a standardized mechanism in Linux which can be used to tie usernames to user IDs without actually creating a system account that can log in? It would seem something like this is possible, ...
3
votes
1answer
2k views

How passwd command from non-root account succeeds

I am trying to change my password as a non root user : passwd The data is updated in /etc/shadow, but checking the permission i get: ---------- 1 root root 6076 Jan 27 17:14 /etc/shadow cat /etc/...
2
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1answer
1k views

NIS and /etc/passwd

Shadow passwords are to be avoided in a NIS server, as suggested in this guide at paragraph 7.6. So: in a NIS server (a Unix or Unix-like system), should all the users be migrated to /etc/passwd from ...
2
votes
1answer
4k views

/etc/shadow encryption method

http://www.aychedee.com/2012/03/14/etc_shadow-password-hash-formats/ From the above article I can see the password can be encrypt in abot 6 different ways to genereate the hash in the format of $1$ .....
5
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2answers
1k views

How to influence the assignment of subordinate UIDs/GIDs when creating user accounts?

To my knowledge the subordinate UIDs and GIDs are assigned to accounts in such a manner that they form a contiguous range. The range starts at 100000 by default and probably stretches to the ...
7
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1answer
2k views

Subordinate GIDs/UIDs with LXC and userns for unprivileged user?

When using userns (via LXC in my case), you assign a range of subordinate GIDs and UIDs to an unprivileged user. See for resources: subuid(5), subgid(5), newuidmap(1), newgidmap(1), user_namespaces(7)....
2
votes
1answer
1k views

What's the correct way to authenticate a user without PAM?

as my related question doesn't seem to get much love, here another one: What's the proper way to authenticate a user via username/password prompt in Linux nowadays? In principle, I suppose I would ...