I'm use an Debian based OS here on my work an i've configured the service for test routines of ERP app...
This service (Tomcat+Java service) it's consumed via HTTP on intranet correctly...but the test leader sometimes need chance the database used by service application and uses SSH to access my machine to change database on config file and restart the service...eventually this person change some service or O.S. config throwing problems to me (on my O.S and others things..).
What i want know is if can i change my password only for SSH service (doesn't change to my KDE/Gnome session), just because the company's policy requires everyone to have a default password on stations...
Remebering that i'm a manager of config, maintenance and others jobs of service to test team...and change database solicitations can made to me.
A simple example:
KDE login if user 'carlos' and password '123456'
SSH login if user 'carlos' and password '4nyJokeHere'
That it's possible ?
Thanks in advance.
Possible? Maybe. You'd probably have to fiddle with pam.d to get SSH authenticating via a different mechanism to KDE etc.
Coming from a different angle, I may be missing something, can you not create a second user for the SSH process, keeping your main user for KDE etc cleanly separate?
I'd really strongly recommend trying to "split" a user into multiple purposes/security groups with differing passwords for each!
You can use authorized_keys to restrict the SSH commands available, and/or sudo...
Update: Some expansion on the subject as requested by the OP
You can limit commands available via SSH by using ~/.ssh/authorised_keys file - see O'Reilly for a good explanation.
I'm was solved this case applying a single rule here. On SSH service i'm was locked access of my user 'carlos --> sudoers' and enable access only for a user called 'padrao' (padrao translated to english is 'default').
This user 'padrao' doesn't have sudoers permissions. If i needed access with SSH my machine i'm do:
ssh padrao#my.intranet.machine
password: ***
$ su carlos
password: ***
This is not the best way to solve, but solved my problem here.
Thanks.
Related
I've created a new instance of AMI Oracle Database 11.2.0.1 64-bit Standard Edition; ami-3f739c56 supplied by Oracle. I've tried to access the instance via SSH from my Windows 10 PC (also from my Mac) but I get the error "Server refused our key. Disconnected: No supported authentication methods available (server sent: publickey, gssapi-with-mic)". I've tried:
User IDs: root; oracle; admin; ec2-user
restarting the instance
rebuilding the key-pairs
Searching Stack Overflow for anything related to this type of problem (everything I've found is out of date by several years and seem to related only to Ubuntu)
searching Oracle's site
searching the Internet
The key-pair that I initially used is fine for my Ubuntu instance that I'm able to connect (User ID: admin).
Everything that I've found so far points to the problem being with me using the wrong default User ID but I don't have anything to tell me what the correct User ID should be.
Any suggestions will be greatly appreciated.
Thanks.
In the AWS Marketplace, navigate to the AMI page
Click on the Usage tab
Click on View Usage Instructions
Note that if the vendor is clckwrk Ltd, then the user is clckwrk
(I did not find OP's "ami-3f739c56")
check health of your AMI:
In the navigation pane, choose Instances, and select the instance.
Choose Actions, Instance Settings, Get System Log.
Write to AWS support.
In my experience there are very "stupid" mistakes:
instance not allow ssh connection, check aws security groups and network acl
you have a typo when you connect via ssh
you have wrong permissions to the ssh key,
or you use wrong ssh key )
try -vvv parameters for ssh command, maybe you can see the erors
The user 'root' worked for me. When I logged in for the first time using 'root' user, it walked me though the Oracle setup process.
I faced the problem too. The username is: clckwrk
I am using FileZilla to log in to an SFTP host with my credentials. However, I need to use an equivalent of sudo su - user (as used in linux) to change the user. There are no passwords set for this general user, and hence direct login is not allowed.
What FTP command can I use with the "Enter custom command.." option in FileZilla to switch users after connecting?
(This is required so I can transfer files as a different user and not my login.)
SFTP protocol doesn't support changing user in the middle of transfer session (so no case to login and then change user with some custom command). But you can launch sftp server under needed user using sudo, by changing SFTP client configuration. Don't know whether this trick is supported by FileZilla, but it's supported by PuTTY or WinSCP. There in the sftp server settings you can specify something like "sudo /bin/sftp-server" in order to launch transfer session under different user.
For example, instruction how to do this with WinSCP:
https://winscp.net/eng/docs/faq_su#sudo
Here are some details about my setup...
Current environment:
40+ *nix systems managed by 6 admins
Highly secure, closed network (no internet access)
Regularly audited (all account passwords must be changed every 90 days)
Current procedures:
Each administrator has a personal account with sudo access. These admin accounts are managed via Active Directory so password changes are not an issue
Root account is also active for specific circumstances (i.e. admin account is locked out)
When it comes time to change the root passwords, an admin will do so by SSHing into each system (40+)
I want to write a script to make the root password changing process more efficient and everything I've read indicates that the most secure way to go about it is by using public key authentication. So my question is: If I log in as root to SYSTEM_1 and set up the public/private key pairs between that system and SYSTEM_2, SYSTEM_3, etc, does that mean I will only be able to run the script from SYSTEM_1? Is this even a good idea security wise? Are there any other ways to script this that I am missing?
You can use RSA Authentication and expect script
Let's say you are executing expect script on system 1, create public-private key pair and store public key on all the other systems you have to login (system 2.....n)
Now you wont need a password when you ssh into those system.
Now you can use expect script to change password for either root or any other user.
NOTE : usually expect interpreter is at /usr/bin/expect
you can find this my doing "whereis expect"
I hope it helps.
Try to use this algorithm and post your results.
I have the following setup:
A server (centOS) with git and a repository for a project on the same server.
What I need to do is to be able to pull from the repository without being asked for password (because is annoying).
Note: I am logged as root when I pull.
Can anyone help me with that?
There are a few options, depending on what your requirements are, in particular your security needs. For both HTTP and SSH, there is password-less, or password required access.
HTTP
==============
Password-Less
Useful for fetch only requirements, by default push is disabled. Perfect if anonymous cloning is the intention. You definitely shouldn't enable push for this type of configuration. The man page for git-http-backend contains good information, online copy at http://www.kernel.org/pub/software/scm/git/docs/git-http-backend.html. It provides an example of how to configure apache to provide this.
User/password in .netrc or url embedded
Where .netrc files are using in the form:
machine <hostname> login <username> password <password>
And embedded urls would be in the form:
http://user:pass#hostname/repo
Since git won't do auth for you, you will need to configure a webserver such as apache to perform the auth, before passing the request onto the git tools. Also keep in mind that using the embedded method is a security risk, even if you use https since it is part of the url being requested.
If you want to be able to pull non-interactive, but prevent anonymous users from accessing the git repo, this should be a reasonably lightweight solution using apache for basic auth and preferably the .netrc file to store credentials. As a small gotcha, git will enable write access once authentication is being used, so either use anonymous http for read-only, or you'll need to perform some additional configuration if you want to prevent the non-interactive user from having write access.
See:
httpd.apache.org/docs/2.4/mod/mod_auth_basic.html for more on configuring basic auth
www.kernel.org/pub/software/scm/git/docs/git-http-backend.html for some examples on the apache config needed.
SSH
==============
Passphrase-Less
Opens up for security issues, since anyone who can get a hold of the ssh private key can now update the remote git repo as this user. If you want to use this non-interactively, I'd recommend installing something like gitolite to make it a little easier to ensure that those with the ssh private key can only pull from the repo, and it requires a different ssh key pair to update the repo.
See github.com/sitaramc/gitolite/ for more on gitolite.
stromberg.dnsalias.org/~strombrg/ssh-keys.html - for creating password less ssh keys:
May also want to cover managing multiple ssh keys: www.kelvinwong.ca/2011/03/30/multiple-ssh-private-keys-identityfile/
Passphase protected
Can use ssh-agent to unlock on a per-session basis, only really useful for interactive fetching from git. Since you mention root and only talk about performing 'git pull', it sounds like your use case is non-interactive. This is something that might be better combined with gitolite (github.com/sitaramc/gitolite/).
Summary
==============
Using something like gitolite will abstract a lot of the configuration away for SSH type set ups, and is definitely recommended if you think you might have additional repositories or need to specify different levels of access. It's logging and auditing are also very useful.
If you just want to be able to pull via http, the git-http-backend man page should contain enough information to configure apache to do the needful.
You can always combine anonymous http(s) for clone/pull, with passphrase protected ssh access required for full access, in which case there is no need to set up gitolite, you'll just add the ssh public key to the ~/.ssh/authorized_keys file.
See the answer to this question. You should use the SSH access instead of HTTPS/GIT and authenticate via your SSH public key. This should also work locally.
If you're using ssh access, you should have ssh agent running, add your key there and register your public ssh key on the repo end. Your ssh key would then be used automatically. This is the preferred way.
If you're using https access, you one would either
use a .netrc file that contains the credentials or
provide user/pass in the target url in the form https://user:pass#domain.tld/repo
With any of these three ways, it shouldn't ask for a password.
I have a remote server to which I login using ssh. Is there a way to be notified through email (using a bash script) when someone changes the user password using passwd including the new password?
I am guessing it has to do with /etc/pam/passwd, but not entirely sure what the trigger and flags should be.
This would be useful if for example I give my access to a "friend" and they decide to lock me out of my account. Of course I could create a new account for them etc, but this is more of a "it should be possible" task rather than a practical one.
First, a Dope Slap
There's a rule that this question reminds me of... What is it? Oh yeah...
NEVER SHARE YOUR PASSWORDS WITH ANYONE!
Which also goes well with the rule.
NEVER SEND SOMETHING SECRET THROUGH EMAIL!
Sorry for the shouting. There's a rule in security that the likelihood a secret will get out is the square of the number of people who know it. My corollary is:
if ( people_who_know_secret > 1 ) {
It ain't a secret any more
}
In Unix, even the system administrator, the all powerful root, doesn't know your password.
Even worse, you want to email your password. Email is far from secure. It's normally just plain text sent over the Aether where anyone who's a wee bit curious can peek at it.
Method One: Allowing Users to use SSH without Knowing Your Password
Since you're using SSH, you should know that SSH has an alternate mechanism for verifying a user called Private/Public keys. It varies from system to system, but what you do is create a public/private key pair. You share your public key with the system you want to log into, but keep your private key private.
Once the remote machine has your public key, you can log into that system via ssh without knowing the password of that system.
The exact mechanism varies from machine to machine and it doesn't help that there are two different ssh protocols, so getting it to work will vary from system to system. On Linux and Macs, you generate your public/private key pair through the ssh-keygen command.
By default, ssh-keygen will produce a file called $HOME/.ssh/id_rsa.pub and $HOME/.ssh/id_rsa. The first one is your public key. You run ssh-keygen on both your machine and the machine you want to log into.
On the machine you're logging into, create a file called $HOME/.ssh/authorized_keys, and copy and paste your public key into this file. Have your friend also send you his public key, and paste that into the file too. Each public key will take up one line in the file.
If everything works, both you and your friend can use ssh to log into that remote machine without being asked for a password. This is very secure since your public key has to match your corresponding private key. If it doesn't you can't log in. That means even if other popel find your public key, they won't be able to log into that remote system.
Both you and your friend can log into that system without worrying about sharing a password.
Method Two: A Better Solution: Using SUDO
The other way to do this is to use sudo to allow your friend to act as you in certain respects. Sudo has a few advantages over actually sharing the account:
All use of SUDO is logged, so you have traceability. If something goes wrong, you know who to blame.
You can limit what people can do as SUDO. For example, your friend has to run a particular command as you, and nothing else. In this case, you can specify in the /etc/sudoers file that your friend can only run that one particular command. You can even specify if your friend can simply run the command, or require your friend to enter their password in order to run that command.
On Ubuntu Linux and on Macintoshes, the root password is locked, so you cannot log in as root. If you need to do something as root, you set yourself up as an administrator (I believe by putting yourself in the wheel group) and then using sudo to run required administrator functions.
The big disadvantage of Sudo is that it's more complex to setup and requires administrator access on the machine.
Try setting up public/private keys using SSH. It might take some tweaking to get it to work, but once it works, it's beautiful. Even better, you can run remote commands and use sep to copy files from one machine to the other -- all without the password prompt. This means that you can write shell scripts to do your work for you.
By the way, a sneaky trick is to set your remote shell to /bin/false. That way, you can't log into that system -- even using ssh, but you can run remote commands using ssh and use sep to copy files back and forth between systems.
Personal passwords are only supposed to be known by the user themselves. Not even the root user is supposed to know them, which is why they are stored encrypted. Of course, the root user has sufficient access to decrypt them, but the principle is the same.
If you are giving your "friend" access, them assign them proper privileges! Do not make them a root user, and you shouldn't be a root user either. Then you're "friend" won't have access to change your password, let along muck about in areas they aren't supposed to be in.
If you absolutely must monitor the passwd and shadow files, install iwatch. Then set it to watch the /etc/passwd and /etc/shadow files. If they change, it runs a script that decrypts the file and emails someone. If you keep a copy to diff against, you'll even know who changed. You should probably also gpg the email, so that it does not go over the internet in plain text, since it has everyone's password in it. Please note that any other users on the system will be upset by the dystopian world they find themselves in.
Just because root is the law of the land does not mean we want to be living in 1984.
Try some kind of:
alias passwd='passwd && echo 'Alert! Alert! Alert!' | mail -s 'pass change' alert#example.com'
Should be enough for you:)
Another possible solutions for those, who think, that alias is too mainstream)) :
1) You could make a cron job, that will be checking your /etc/shadow file every, for example, minute, and when the file changes, it will send you an alert-email. The easiest way here, I think, will be making md5 checksum
2) You can move /usr/bin/passwd to /usr/bin/passwd.sys and make a script with /usr/bin/passwd.sys && echo 'Alert! Alert! Alert!' | mail -s 'pass change' on it's place. And yes, this way is also could be discovered be the user and scrubed round:)