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Questions tagged [shadow]

The tag has no usage guidance.

3
votes
1answer
72 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
158 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
54 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
votes
0answers
48 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 ...
0
votes
0answers
21 views

Compare/validate a shadow file hashed password with a manually hashed password? [duplicate]

In MySQL, I can validate a password by manually hashing a password using the PASSWORD function in the WHERE clause. e.g. mysql> SELECT User, Host FROM mysql.user WHERE Password LIKE PASSWORD('...
-6
votes
1answer
69 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
votes
3answers
577 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
votes
1answer
58 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 ...
1
vote
2answers
580 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
votes
1answer
103 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
votes
0answers
20 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 ...
3
votes
1answer
2k 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
votes
1answer
866 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
180 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
258 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-...
2
votes
1answer
40 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
497 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
609 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
votes
1answer
322 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
votes
1answer
76 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 "!" ?
4
votes
0answers
2k 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
4k 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 ...
81
votes
3answers
6k 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
180 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
343 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 ...
29
votes
2answers
32k 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
210 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
8k 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 ...
0
votes
2answers
243 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
votes
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
361 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
196 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
votes
1answer
950 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
3k 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 $1$ .....
3
votes
1answer
764 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 ...
6
votes
1answer
1k 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 ...
7
votes
1answer
2k views

SHA512 salted hash code question

I'm puzzled by the hash (ASCII) code stored under Linux (Ubuntu) /etc/shadow. Taking a hypothetical case, let password be 'test', salt be 'Zem197T4'. By running following command, $ mkpasswd -m SHA-...
27
votes
2answers
46k 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$...
2
votes
1answer
164 views

Why is there a ! in the password hash?

In /etc/shadow, I have a line that begins: ubuntu:!$6$Pi4BKmX8$........................ Why is there a ! before the $6$ in the hash?
3
votes
1answer
1k views

How does Linux verify the login password?

I would like to know how the password verification in Linux works. I know that the passwords are stored as a hash in /etc/shadow file and user information is in /etc/passwd file. My understanding ...
0
votes
1answer
240 views

Store passwords of Linux users in plain text - on purpose [duplicate]

I want to reset passwords temporarily to log in as root at least one time to change passwords. I have access to the hard drive and I can run a live distro to gain root access. I did think it would be ...
5
votes
2answers
2k views

Is it possible to change passwords temporarily?

I have a Linux system with several users. I don't know their passwords, nor do I want to know them. I have to do a batch copy of some of their directories over SSH, with their account and password. ...
8
votes
3answers
2k views

Root and my password are the same

If I cat /etc/shadow I can get the encrypted passwords of root and my user. These passwords are the same (I know, bad security) for each account, but in /etc/shadow they show up as being different ...
1
vote
1answer
177 views

How does the authentication process with the salted hash in shadow work

Does the supplied password during login get converted to a salted hash and then compared to the one in /etc/shadow? /what if the user is in LDAP but not in the shadow file? Would it use kerberos?
1
vote
1answer
3k views

HOWTO check if a user account is blocked against /etc/shadow

After set the Account Expire parameter on /etc/shadow (field #7) to 90 days,I need to know where to look around if an user account is locked down or not after those amount of days. Right now, the ...
1
vote
1answer
399 views

shadow files getting created automatically in /etc in solaris server.(SunOS 5.10)

In my Solaris server (SunOS 5.10) shadow files are getting created automatically every 10 minutes for two particular users in /etc. The content of the files is the same as /etc/shadow. Say john and ...
1
vote
0answers
94 views

How shadow a file to point to something else?

Case: VirtualBox doesn't support Windows' symlink to be shared with host (Linux). actually a physical folder which contains the link is share. Everything except the symlink can be accessed. Have a ...
6
votes
4answers
29k views

Two ways to lock a password but only one to unlock

CentOS 6 Linux has two ways to lock a password: passwd -l usermod -L Today I found out, that they do something different. passwd writes two exclamation marks into the shadow file. # passwd -d ...