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0
votes
1answer
63 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
33 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 ...
3
votes
2answers
33 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. ...
7
votes
2answers
560 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
36 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
108 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
71 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
36 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 ...
3
votes
2answers
456 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 ...
1
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0answers
25 views

Contentless modal windows on RHEL Gnome

I'm a Linux newbie, so please be understanding if I mix terminology. I've got a pc with RHEL 6.4 installed. I'm using Gnome for my GUI and frequently I'm having a problem with modal windows ...
0
votes
2answers
150 views

How to backup /etc/{,g}shadow files with 0000 permission?

I am trying to backup several servers' /etc by using rsync from another server. Here's a relevant snippet: PRIVKEY=/path/to/private.key RSYNC_OPTS="--archive --inplace --no-whole-file --quiet" ssh -n ...
2
votes
2answers
197 views

How do I switch from /etc/shadow back to /etc/passwd?

I'm playing with a rather old, heavily customized Linux installation (based on Debian etch, running on a Netgear ReadyNAS device). Recently I've switched from /etc/passwd to /etc/shadow via pwconv. ...
2
votes
1answer
1k views

Unix last password change date

My understanding is that the last change date(in /etc/shadow) is the number of days since 01/01/1970 that the password was changed, but I'm seeing numbers like 19708 which translate to 17/12/2023 ...
7
votes
1answer
720 views

why have programs like su access to /etc/shadow

Normally only root can access /etc/shadow. But programs like su and sudo can check passwords without running as root. So the question is: Why can these programs access /etc/shadow without privileges? ...
3
votes
2answers
225 views

Change password through linux PAM without running application as root

An application I'm writing will have some password change functionality. However I'm wondering if it is possible to not run the account management part of it as root. Right now I'm running into the ...
7
votes
1answer
8k views

Manually generate password for /etc/shadow [duplicate]

I need to manually edit /etc/shadow to change the root password inside of a virtual machine image. Is there a command-line tool that takes a password and generates an /etc/shadow compatiable password ...
1
vote
2answers
314 views

Perl - /etc/shadow - Permission Denied

The following command is being executed by a non root user : perl -pi -e 's/^an24:/an24:\*LK*/g' /etc/shadow A permission denied is being issued. This indicates some privileges issues. Can such ...
1
vote
3answers
228 views

Why isn't there standard library to modify /etc/{passwd, shadow}?

Why doesn't glibc provide standard library to modify /etc/passwd and /etc/shadow, i.e add a user, change passwd, I came to that conclusion because I checked the source code of shadow and failed to ...
2
votes
3answers
8k views

What's the meaning of NP and UP in the password field of the shadow file

I found some entries in a shadow file whose meaning I don't understand. user:UP::::::: user1:NP::::::: What does UP and NP mean? In addition to those 2, the same shadow file has the normal hashed ...
3
votes
1answer
244 views

Can linux use a mix of SHA-1 and CRYPT passwords?

We have an automated sync-routine that uses useradd to create new users on a Ubuntu 10.04 machine. The application launching the routine provided both username and CRYPT-encrypted password. However, ...
7
votes
1answer
165 views

Is it normal to have a file called “shadow-” in the /etc directory?

I am noticing a lot of weird files appearing in my router and on my various filesystems. Files in weird places or files that have to do with security with a - sign after them. If I do ls -l ...
4
votes
2answers
2k views

/etc/shadow and /etc/passwd format compatibility

Are formats of files /etc/shadow and /etc/passwd same on all unix and unix-like systems same or are there significant differences? I mean syntax of files, not file location or name
4
votes
3answers
713 views

Extract dates from /etc/shadow

The file /etc/shadow has a couple date fields that are expressed as the number of days since Jan 1, 1970. Is there an easy way using to get a list of users and the calendar date of the last password ...
1
vote
1answer
312 views

Why the inode value of shadow file changes?

I created a hard link for the shadow file. For removing the passwd of the user I opened the shadow file in vi editor and removed the encrypted passwd and then saved. The inode value of the shadow file ...
3
votes
2answers
2k views

Second field in /etc/shadow

If the second field of the /etc/shadow file is set to !!, does it mean that the account is disabled? Or does it mean that the account is active with no password assigned?