Server :: Changes Happened In /etc/shadow File, When User Changing Password?
Jan 24, 2011
I want to know, how does changes happened in the encrypted password in /etc/shadow file , when user changing password . because user doesnot have access on that file
I am working on building a customized ISO image of a server based on linux. The thing is after the server is installed and run for the first time, three users have to be created for the various services to run properly. I want this to be automated. To achieve this what is was thinking is automatically enter the user entries in the /etc/passwd and /etc/shadow files through init scripts when the server starts for the first time after the installation. I tried creating user and assigning password in one of my machine, and the /etc/passwd and the /etc/shadow entries of this user I copied it into the other machine and tried login in on the other machine and everything worked fine. How I am trying to achieve this.
I am trying to write a remote access module. Is there any function in linux where I can give string (password entered by user) and compare it with the actual user password stored in /etc/shadow. Since the password is stored encrypted in /etc/shadow I cannot parse and compare. So I want some method to compare if my user entered the correct password..Is there any function for that..
Today i was going through some of security guides written on linux .Under shadow file security following points were mentioned.1)The encrypted password stored under /etc/shadow file should have more than 14-25 characters.2)Usernames in shadow file must satisfy to all the same rules as usernames in /etc/passwd.3)password for application Username should display * if username is not locked.4)If a user is locked it should be displayed as ! as the first character in second field of shadow file.
Confusion for point 1 and 2:Now i m confused as why the encrypted password should be more than 14-25 characters.Also what rules to satisfy How to check it?Confusion for point 3 and 4:There are lot of users with * as second field i guess they are not locked but according to 4th point there are lot of users with ! as first characters.How would i check whether they are actually locked or not.I m posting the output of /etc/shadow and /etc/passwd files for the account.
I noticed that our /etc/shadow file is readable on a patch I released for one of our in house linux boxes a while back ago. Could they use it to gain access the root account etc? Our passwords are all MD5 encrypted.
i am new to debian. I need to know after booting sequence login shell appears to get username and password. so what happens when user puts username and password ?? how this given username and password are matched with /etc/shadow file ??
my another question is what is role of /etc/pam.d/ authenticating username and password ?? does it work with shadow file or not ?
I would like to grep all values other than encrypted password from /etc/shadow fileFor example,each line consists of 8 fields separated with :/The only thing that I want not to print out is the contents between first : and second : (encrypted password)
I've been trying to write php or perl code to generate the sha-512 password hashes in fedora. I've been unable to do the hashing which is encoded in the shadow file on fedora core 11. Does anyone have php or perl code which provides the hashing algorithm. (All of my attempts result in the encrypted hashing being longer than 86 character -- the length that crypt says the sha-512 should be)
I'm running RHEL 5. When using the GUI System>Administration>Users and Groups, I get the error: The user database cannot be read. This problem is most likely caused by a mismatch between /etc/passwd and /etc/shadow or /etc/group and /etc/gshadow. The program will exit now.
Some research showed that I need to use vipw and vigr respectively to find an inconsistency between these two sets, which I did - to make it easy I copied each from [vipw | vigr] to an excel file and did =exact(%1, %2). There are no inconsistencies.
I hope I am in the right forum. I have a question about restricting users from being able to change their own passwords in Fedora 10. In Fedora 6, I was able to do this by using passwd with -n and -x flags. If I would set the -n value greater than the -x value, then the user would not be able to change his/her own password. If I do this in Fedora 10, this no longer works
I'm looking for a user-friendly way to change the password of a user that is *not* currently logged into the machine. We have a machine that is used by a number of users with a low level of tech savvy. The machine gets logged in as a generic user which works for most purposes, but due to a management requirement, we need Firefox to be run under an account set up for the individual user. I've gotten that bit to work fine, but what I can't figure out is a friendly (GUI) way to allow users to change their own password while the machine is logged in as the generic user. I would like to use gnome-passwd, but I've been unable to figure out how to get it to run for a user other than the logged-in generic user.
My problem is that I cant "rewrite" older password to new. It looks like I do:
Changing password for user johny. New UNIX password: Retype new UNIX password: passwd: all authentication tokens updated successfully.
all looks OK but after set up new password I can log in using OLD and NEW password. It's very unsecure for me. So in fact I cant change password and it looks like centos create next password to one accout and one account have more then one password... how can I prevent it? pls help me couse its very unsecure in my case.user looks in file shadow /etc/shadow like this:
I'm looking to find out exactly how to go about changing the encryption method of shadow passwords from MD5 to something a bit stronger, like SHA. I've been looking around for a bit now and haven't found out how to do it. I've gathered that I'll most likely need to change the /etc/pam.d/system-auth file. Right now, there is a line that looks like this:
password sufficient pam_unix.so md5 shadow nullok try_first_pass use_authtok.I'm guessing the md5 should be changed to something else, like sha256. What else? I know I'll need to reset all passwords once the change is made, but I thought there was someplace else that controls how the passwd command encrypts passwords.
I want to add 50 new users, not on the server yet I want to add them all to group Accounting - with 1 option, not user by user I want to setup a default password for them all, and have it say something like 'You must now change password or no access will be permitted' Any other options I also want to do once, not for each user?
My bose ask me to convert a CentOS system password like "LMPQSMTE0nHlQ" to postfix MySQL MD5 Hased password, I find CentOS seems has 2 kinds of password form, one is shorter and the other is very long like"$1$C2MSk16n$WT5JWnzYH7XpCCjsiE2bd1", however I find postfix is exactly the later long one, so does any one know how to convert the short form to the later one
I am moving my Linux server from Suse 10 to Ubuntu 9.04 and I moved the significant parts of /etc/shadow, /etc/passwd, and /etc/group over to Ubuntu 9.04. I am not able to login into the computer with the old accounts. The only problem I see is that the old accounts use Blowfish and DES to encrypt the passwords in /etc/shadow, and Ubuntu uses SHA512. If I change the passwords, the accounts will work. However; I have about 300 accounts to move, and I don't want to do that to all of them. I have tired Ubuntu Forums and talked to every linux expert I know, and no one has an answer.
The /etc/shadow file contains an id of $1$, $2$, $5$ or $6$ to show the encryption method used.A salt follows this,followed by the password hash.When a user is created and a password is set, a hash is RANDOMLY generated and used as the salt to the password hash. Everytime that user logs in, login checks /etc/shadow for the $id$ and salt and runs the password given by the user through the hash mechanism ($id$) using the salt in /etc/shadow.So basically does login look at /etc/shadow for the $id$ and salt to create a hash with which to compare to the /etc/shadow hash?question 2 - If my $id$ was $5$, which is sha256, how would i go about changing this? Like is there a shadow.conf or crypt.conf or something? Can i change it per user?
I need to manually convert an string ( like with echo ) to a DES crypt format to be inserted inside a /etc/shadow file, does anybody knows how can I do that?
Maybe there are some little tool that could handle that operation, well.. I don't know, hope someone can give me a hint on that.
I need to create a script that returns a list of the users who have never changed their password from /etc/shadow. As I know on linux there is a command "chage" used for find last password change.
I have a quick questions about MD5-sums in the /etc/shadow file: One of our third party software products have created some new system accounts on our RHEL servers like this (sysuser is the system account, while user1 is a regular user account) code...
I have configured a FTP (VSFTPD) Server in RHEL 5.6, which resulted me a default directory /var/ftp/pub. Even i have cerated another Directory /var/ftp/accounts. Where Accounts Directory is owned by user x in my server. I have a issue with this, It prompts me User and Password while accessing this ftp 192.168.5.20 in Linux Servers. But while i am trying this through a windows machine by ftp://192.168.5.20 it gets directly accessed without prompting me any User and Password.
I need to have FTP environment same like windows. where it must prompt me user name and password, and i must be able to upload and download data from my windows clients.
I have configured Ldap Server in CentOS 5.4 & it's working fine, the problem is when I create a ldapuser from server the user can login in client machine but the user has no rights to change the password. How to rectify this by using commands.
How do my user change password in webmail because there is no option to change password in my webmail. How to change password in webmail. I am using centos5.
I recently mashed the passwd, shadow, gshadow, group files in my Fedora 12 installation. I was dumb and didn't take a copy of the originals and all I have is the originals from a Fedora 11 installation.
My goal is this: Allow a user to connect to a server via SSH with any login name or password without checking to see if that account exists on that server. Their account would be captured by a universal account say, 'generic_user', and then they would be directed to one of my python scripts with the username and password they supplied for initial login. At this point my script would capture their SSHD process ID and allow/deny their existence based upon a MySQL/Subscription check.
The part I'm having trouble with is with PAM and allowing the user to login with any credentials and be successfully authenticated under the generic account. Beyond that, everything is great.