Following Christian Schneider's blog post, How to hack into any default apache karaf installation, I checked to see if my default Karaf installation (4.0.5) is insecure:
Some simple steps to check if your karaf installations is open.
Check the "etc/org.apache.karaf.shell.cfg" for the attribute sshPort. Note this port number. By default it is 8101
Do "ssh -p 8101 karaf#localhost". Like expected it will ask for a password. This may also be dangerous if you do not change the default password but is quite obvious.
Now just do bin/client -a 8101. You will get a shell without supplying a password. If this works then your server is vulnerable
As expected. It is vulnerable. So I tried to secure it following the instructions as described:
How to secure your server?
Simply remove the public key of the karaf user in the "etc/keys.properties". Unfortunately this will stop the bin/client command from working.
Also make sure you change the password of the karaf user in "etc/users.properties".
I shut down the Karaf server using the halt command. Then I changed the karaf password in etc/users.properties and deleted the file etc/keys.properties. Then I started the server again with bin/karaf. Then in a new terminal I tested to see if the installation was secure by trying to ssh into the server. I validated that ssh login now requires the newly configured password. Finally, I tried using the bin/client -a 8101 command.
At this point, as explained in the blog post, I expected the command to fail:
Unfortunately this will stop the bin/client command from working.
I noticed after running bin/client -a 8101 there is a new file etc/host.key that either bin/client or the container itself auto generated. Rather than failing the command succeeded and I was presented with the Karaf console.
Does this means the container is still vulnerable to this attack vector?
No.
The modifications described in the OP (changing the default password in etc/users.properties and deleting etc/keys.properties) secures the container from that specific attack vector.
According to the discussion on the Karaf users mailing list concerning this stack overflow question:
By default bin/client tries (in this order) to use:
etc/keys.properties
etc/users.properties
karaf/karaf
-u to prompt for the password
bin/client is an SSH client (written in Java). The host.key is the same file as for SSH and containing the trusted hosts (you also have .sshkaraf/known_hosts for that).
The section quoted from the blog in the OP is out dated:
Unfortunately this will stop the bin/client command from working.
I am changing different parameters like RSAAuthentication, PubkeyAuthentication and PasswordAuthentication (sudo vim /etc/ssh/sshd_config) to disable ssh password authentication to force ssh login via public key only.
The experiments are adversely affecting many users as they suddenly find "Connection refused" while trying to ssh to the server. I want to avoid these experiments. Is there any work around to enable public key authentication without touching system files like /etc/ssh/ssd_config?
Sure. Set up an alternative configuration file, and run sshd on another port while you are experimenting:
cp sshd_config sshd_config_working
/usr/sbin/sshd -p 2222 -f sshd_config_working
Now you can connect with:
ssh -p 2222 user#localhost
And you can make as many changes as you want until you it working as desired. At that point, copy your _working config back to the main config file and restart sshd.
Alternatively, stop mucking about on a production server and set up a virtual machine or cotainer for testing, where you can modify the sshd configuration as much as you want without affecting anybody.
I've installed GitLab on Google Compute Engine using "Click to Deploy" from the project interface. The deployment is successful after a few minutes. I can SSH into the instance, and muck around with it as expected.
I can also log in to GitLab using the web interface, and add SSH keys to my profile. So far, so good. However, when I attempt to push or pull to a new example repository, I receive this message:
Permission denied (publickey,gssapi-keyex,gssapi-with-mic).
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.
I've removed my local SSH config so it doesn't interfere. Do I need to setup an SSH tunnel of some sort? What am I missing?
UPDATE: Wiping out my local ~/.ssh folder, and regenerating an SSH key (which I've added to my profile in GitLab) produces the following error:
Received disconnect from {GITLAB_IP_ADDRESS}: 2: Too many authentication failures for git
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.
UPDATE 2: It seems GitLab may already have a solution: run sudo gitlab-ctl reconfigure. See here: https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/README.md#git-ssh-access-stops-working-on-selinux-enabled-systems
You need to create an SSH tunnel to communicate with GitLab.
1. Log into your development server as your user, and create a key.
ssh-keygen -t rsa
Follow the steps, and create a passcode (that you can remember) as you'd need this to pull and push code from/to GitLab.
2. Now that you've created your key, we can copy it;
cat id_rsa.pub
Copy the output of that command (including ssh-rsa), and add it to your GitLab profile. (http://my-gitlab-server.com/profile/keys/new).
3. Ensure you have the correct privilege to the project(s)
Ensure you are at role developer at the very least. (Screengrab of roles: http://i.stack.imgur.com/DSSvl.jpg)
4. Now, copy the project link
Go into your project, and find the SSH link in the top right;
5. Now back to your development server
Navigate to your directory where you'd like to work, and run the following;
$ git init
$ git remote add origin <<project_url>>
$ git fetch
Where <<project_url>> is the link we copied in step 4.
You will be prompted your password (this is your ssh key password, not your server password) and to add the host to your known_hosts file. After that, the project will start to download and you can enjoy development.
I did these steps on a CentOS 6.4 machine with Digital Ocean. But they shouldn't differ from using Google CE.
Edit
Quote from Marty Penner answer as per this comment
Solved it! Thanks to #sxleixer and #Alexander Wenzowski for figuring this out.
Apparently, SELinux was interfering with a non-standard location for the .ssh directory. I needed to run the following commands on the Compute Engine instance:
sudo yum -y install policycoreutils-python # Install the `semanage` tool
sudo semanage fcontext -a -t ssh_home_t "/var/opt/gitlab/.ssh/authorized_keys" # Allow the nonstandard ssh_home_t
See the full thread here:
Google Cloud Engine. Permission denied (publickey,gssapi-keyex,gssapi-with-mic)
Solved it! Thanks to #sxleixer and #Alexander Wenzowski for figuring this out.
Apparently, SELinux was interfering with a non-standard location for the .ssh directory. I needed to run the following commands on the Compute Engine instance:
sudo yum -y install policycoreutils-python # Install the `semanage` tool
sudo semanage fcontext -a -t ssh_home_t "/var/opt/gitlab/.ssh/authorized_keys" # Allow the nonstandard ssh_home_t
See the full thread here:
Google Cloud Engine. Permission denied (publickey,gssapi-keyex,gssapi-with-mic)
UPDATE: It seems GitLab may already have a solution: run sudo gitlab-ctl reconfigure. See here: https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/README.md#git-ssh-access-stops-working-on-selinux-enabled-systems
In my situation the git user wasn´t set up completely. If you get in your log files messages like "User git not allowed because account is locked" (Under Centos or Redhat it´s /var/log/secure) than you simply need to activate the user via "passwd -d git"
Is there a way to reset all (or just disable the security settings) from the command line without a user/password as I have managed to completely lock myself out of Jenkins?
The simplest solution is to completely disable security - change true to false in /var/lib/jenkins/config.xml file.
<useSecurity>true</useSecurity>
A one-liner to achieve the same:
sed -i 's/<useSecurity>true<\/useSecurity>/<useSecurity>false<\/useSecurity>/g' /var/lib/jenkins/config.xml
Then just restart Jenkins:
sudo service jenkins restart
And then go to admin panel and set everything once again.
If you in case are running your Jenkins inside a Kubernetes pod and can not run service command, then you can just restart Jenkins by deleting the pod:
kubectl delete pod <jenkins-pod-name>
Once the command was issued, Kubernetes will terminate the old pod and start a new one.
One other way would be to manually edit the configuration file for your user (e.g. /var/lib/jenkins/users/username/config.xml) and update the contents of passwordHash:
<passwordHash>#jbcrypt:$2a$10$razd3L1aXndFfBNHO95aj.IVrFydsxkcQCcLmujmFQzll3hcUrY7S</passwordHash>
Once you have done this, just restart Jenkins and log in using this password:
test
The <passwordHash> element in users/<username>/config.xml will accept data of the format
salt:sha256("password{salt}")
So, if your salt is bar and your password is foo then you can produce the SHA256 like this:
echo -n 'foo{bar}' | sha256sum
You should get 7f128793bc057556756f4195fb72cdc5bd8c5a74dee655a6bfb59b4a4c4f4349 as the result. Take the hash and put it with the salt into <passwordHash>:
<passwordHash>bar:7f128793bc057556756f4195fb72cdc5bd8c5a74dee655a6bfb59b4a4c4f4349</passwordHash>
Restart Jenkins, then try logging in with password foo. Then reset your password to something else. (Jenkins uses bcrypt by default, and one round of SHA256 is not a secure way to store passwords. You'll get a bcrypt hash stored when you reset your password.)
I found the file in question located in /var/lib/jenkins called config.xml, modifying that fixed the issue.
In El-Capitan config.xml can not be found at
/var/lib/jenkins/
Its available in
~/.jenkins
then after that as other mentioned open the config.xml file and make the following changes
In this replace <useSecurity>true</useSecurity> with <useSecurity>false</useSecurity>
Remove <authorizationStrategy> and <securityRealm>
Save it and restart the jenkins(sudo service jenkins restart)
The answer on modifying was correct. Yet, I think it should be mentioned that /var/lib/jenkins/config.xml looks something like this if you have activated "Project-based Matrix Authorization Strategy". Deleting /var/lib/jenkins/config.xml and restarting jenkins also does the trick. I also deleted the users in /var/lib/jenkins/users to start from scratch.
<authorizationStrategy class="hudson.security.ProjectMatrixAuthorizationStrategy">
<permission>hudson.model.Computer.Configure:jenkins-admin</permission>
<permission>hudson.model.Computer.Connect:jenkins-admin</permission>
<permission>hudson.model.Computer.Create:jenkins-admin</permission>
<permission>hudson.model.Computer.Delete:jenkins-admin</permission>
<permission>hudson.model.Computer.Disconnect:jenkins-admin</permission>
<!-- if this is missing for your user and it is the only one, bad luck -->
<permission>hudson.model.Hudson.Administer:jenkins-admin</permission>
<permission>hudson.model.Hudson.Read:jenkins-admin</permission>
<permission>hudson.model.Hudson.RunScripts:jenkins-admin</permission>
<permission>hudson.model.Item.Build:jenkins-admin</permission>
<permission>hudson.model.Item.Cancel:jenkins-admin</permission>
<permission>hudson.model.Item.Configure:jenkins-admin</permission>
<permission>hudson.model.Item.Create:jenkins-admin</permission>
<permission>hudson.model.Item.Delete:jenkins-admin</permission>
<permission>hudson.model.Item.Discover:jenkins-admin</permission>
<permission>hudson.model.Item.Read:jenkins-admin</permission>
<permission>hudson.model.Item.Workspace:jenkins-admin</permission>
<permission>hudson.model.View.Configure:jenkins-admin</permission>
<permission>hudson.model.View.Create:jenkins-admin</permission>
<permission>hudson.model.View.Delete:jenkins-admin</permission>
<permission>hudson.model.View.Read:jenkins-admin</permission>
</authorizationStrategy>
We can reset the password while leaving security on.
The config.xml file in /var/lib/Jenkins/users/admin/ acts sort of like the /etc/shadow file Linux or UNIX-like systems or the SAM file in Windows, in the sense that it stores the hash of the account's password.
If you need to reset the password without logging in, you can edit this file and replace the old hash with a new one generated from bcrypt:
$ pip install bcrypt
$ python
>>> import bcrypt
>>> bcrypt.hashpw("yourpassword", bcrypt.gensalt(rounds=10, prefix=b"2a"))
'YOUR_HASH'
This will output your hash, with prefix 2a, the correct prefix for Jenkins hashes.
Now, edit the config.xml file:
...
<passwordHash>#jbcrypt:REPLACE_THIS</passwordHash>
...
Once you insert the new hash, reset Jenkins:
(if you are on a system with systemd):
sudo systemctl restart Jenkins
You can now log in, and you didn't leave your system open for a second.
To disable Jenkins security in simple steps in Linux, run these commands:
sudo ex +g/useSecurity/d +g/authorizationStrategy/d -scwq /var/lib/jenkins/config.xml
sudo /etc/init.d/jenkins restart
It will remove useSecurity and authorizationStrategy lines from your config.xml root config file and restart your Jenkins.
See also: Disable security at Jenkins website
After gaining the access to Jenkins, you can re-enable security in your Configure Global Security page by choosing the Access Control/Security Realm. After than don't forget to create the admin user.
To reset it without disabling security if you're using matrix permissions (probably easily adaptable to other login methods):
In config.xml, set disableSignup to false.
Restart Jenkins.
Go to the Jenkins web page and sign up with a new user.
In config.xml, duplicate one of the <permission>hudson.model.Hudson.Administer:username</permission> lines and replace username with the new user.
If it's a private server, set disableSignup back to true in config.xml.
Restart Jenkins.
Go to the Jenkins web page and log in as the new user.
Reset the password of the original user.
Log in as the original user.
Optional cleanup:
Delete the new user.
Delete the temporary <permission> line in config.xml.
No securities were harmed during this answer.
On the offchance you accidentally lock yourself out of Jenkins due to a permission mistake, and you dont have server-side access to switch to the jenkins user or root... You can make a job in Jenkins and add this to the Shell Script:
sed -i 's/<useSecurity>true/<useSecurity>false/' ~/config.xml
Then click Build Now and restart Jenkins (or the server if you need to!)
\.jenkins\secrets\initialAdminPassword
Copy the password from the initialAdminPassword file and paste it into the Jenkins.
1 first check location if you install war or Linux or windows based on that
for example if war under Linux and for admin user
/home/"User_NAME"/.jenkins/users/admin/config.xml
go to this tag after #jbcrypt:
<passwordHash>#jbcrypt:$2a$10$3DzCGLQr2oYXtcot4o0rB.wYi5kth6e45tcPpRFsuYqzLZfn1pcWK</passwordHash>
change this password using use any website for bcrypt hash generator
https://www.dailycred.com/article/bcrypt-calculator
make sure it start with $2a cause this one jenkens uses
In order to remove the by default security for jenkins in Windows OS,
You can traverse through the file Config.xml created inside /users/{UserName}/.jenkins.
Inside this file you can change the code from
<useSecurity>true</useSecurity>
To,
<useSecurity>false</useSecurity>
step-1 : go to the directory cd .jenkins/secrets then you will get a 'initialAdminPassword'.
step-2 : nano initialAdminPassword
you will get a password
changing the <useSecurity>true</useSecurity> to <useSecurity>false</useSecurity> will not be enough, you should remove <authorizationStrategy> and <securityRealm> elements too and restart your jenkins server by doing sudo service jenkins restart .
remember this, set <usesecurity> to false only may cause a problem for you, since these instructions are mentioned in thier official documentation here.
Jenkins over KUBENETES and Docker
In case of Jenkins over a container managed by a Kubernetes POD is a bit more complex since: kubectl exec PODID --namespace=jenkins -it -- /bin/bash will you allow to access directly to the container running Jenkins, but you will not have root access, sudo, vi and many commands are not available and therefore a workaround is needed.
Use kubectl describe pod [...] to find the node running your Pod and the container ID (docker://...)
SSH into the node
run docker exec -ti -u root -- /bin/bash to access the container with Root privileges
apt-get update
sudo apt-get install vim
The second difference is that the Jenkins configuration file are placed in a different path that corresponds to the mounting point of the persistent volume, i.e. /var/jenkins_home, this location might change in the future, check it running df.
Then disable security - change true to false in /var/jenkins_home/jenkins/config.xml file.
<useSecurity>false</useSecurity>
Now it is enough to restart the Jenkins, action that will cause the container and the Pod to die, it will created again in some seconds with the configuration updated (and all the chance like vi, update erased) thanks to the persistent volume.
The whole solution has been tested on Google Kubernetes Engine.
UPDATE
Notice that you can as well run ps -aux the password in plain text is shown even without root access.
jenkins#jenkins-87c47bbb8-g87nw:/$ps -aux
[...]
jenkins [..] -jar /usr/share/jenkins/jenkins.war --argumentsRealm.passwd.jenkins=password --argumentsRealm.roles.jenkins=admin
[...]
Easy way out of this is to use the admin psw to login with your admin user:
Change to root user: sudo su -
Copy the password: xclip -sel clip < /var/lib/jenkins/secrets/initialAdminPassword
Login with admin and press ctrl + v on password input box.
Install xclip if you don't have it:
$ sudo apt-get install xclip
Using bcrypt you can solve this issue. Extending the #Reem answer for someone who is trying to automate the process using bash and python.
#!/bin/bash
pip install bcrypt
yum install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
yum -y install xmlstarlet
cat > /tmp/jenkinsHash.py <<EOF
import bcrypt
import sys
if not sys.argv[1]:
sys.exit(10)
plaintext_pwd=sys.argv[1]
encrypted_pwd=bcrypt.hashpw(sys.argv[1], bcrypt.gensalt(rounds=10, prefix=b"2a"))
isCorrect=bcrypt.checkpw(plaintext_pwd, encrypted_pwd)
if not isCorrect:
sys.exit(20);
print "{}".format(encrypted_pwd)
EOF
chmod +x /tmp/jenkinsHash.py
cd /var/lib/jenkins/users/admin*
pwd
while (( 1 )); do
echo "Waiting for Jenkins to generate admin user's config file ..."
if [[ -f "./config.xml" ]]; then
break
fi
sleep 10
done
echo "Admin config file created"
admin_password=$(python /tmp/jenkinsHash.py password 2>&1)
# Repalcing the new passowrd
xmlstarlet -q ed --inplace -u "/user/properties/hudson.security.HudsonPrivateSecurityRealm_-Details/passwordHash" -v '#jbcrypt:'"$admin_password" config.xml
# Restart
systemctl restart jenkins
sleep 10
I have kept password hardcoded here but it can be a user input depending upon the requirement. Also make sure to add that sleep otherwise any other command revolving around Jenkins will fail.
To very simply disable both security and the startup wizard, use the JAVA property:
-Djenkins.install.runSetupWizard=false
The nice thing about this is that you can use it in a Docker image such that your container will always start up immediately with no login screen:
# Dockerfile
FROM jenkins/jenkins:lts
ENV JAVA_OPTS -Djenkins.install.runSetupWizard=false
Note that, as mentioned by others, the Jenkins config.xml is in /var/jenkins_home in the image, but using sed to modify it from the Dockerfile fails, because (presumably) the config.xml doesn't exist until the server starts.
I will add some improvements based on the solution:
https://stackoverflow.com/a/51255443/5322871
On my scenario it was deployed with Swarm cluster with nfs volume, in order to perform the password reset I did the following:
Attach to the pod:
$ docker exec -it <pod-name> bash
Generate the hash password with python (do not forget to specify the letter b outside of your quoted password, the method hashpw requires a parameter in bytes):
$ pip install bcrypt
$ python
>>> import bcrypt
>>> bcrypt.hashpw(b"yourpassword", bcrypt.gensalt(rounds=10, prefix=b"2a"))
'YOUR_HASH'
Once inside the container find all the config.xml files:
$ find /var/ -type f -iname "config.xml"
Once identified, modify value of the field ( on my case the config.xml was in another location):
$ vim /var/jenkins_home/users/admin_9482805162890262115/config.xml
...
<passwordHash>#jbcrypt:YOUR_HASH</passwordHash>
...
Restart the service:
docker service scale <service-name>=0
docker service scale <service-name>=1
Hope this can be helpful for anybody.
I had a similar issue, and following reply from ArtB,
I found that my user didn't have the proper configurations. so what I did:
Note: manually modifying such XML files is risky. Do it at your own risk. Since I was already locked out, I didn't have much to lose. AFAIK Worst case I would have deleted the ~/.jenkins/config.xml file as prev post mentioned.
**> 1. ssh to the jenkins machine
cd ~/.jenkins (I guess that some installations put it under /var/lib/jenkins/config.xml, but not in my case )
vi config.xml, and under authorizationStrategy xml tag, add the below section (just used my username instead of "put-your-username")
restart jenkins. in my case as root service tomcat7 stop; ; service tomcat7 start
Try to login again. (worked for me)**
under
add:
<permission>hudson.model.Computer.Build:put-your-username</permission>
<permission>hudson.model.Computer.Configure:put-your-username</permission>
<permission>hudson.model.Computer.Connect:put-your-username</permission>
<permission>hudson.model.Computer.Create:put-your-username</permission>
<permission>hudson.model.Computer.Delete:put-your-username</permission>
<permission>hudson.model.Computer.Disconnect:put-your-username</permission>
<permission>hudson.model.Hudson.Administer:put-your-username</permission>
<permission>hudson.model.Hudson.ConfigureUpdateCenter:put-your-username</permission>
<permission>hudson.model.Hudson.Read:put-your-username</permission>
<permission>hudson.model.Hudson.RunScripts:put-your-username</permission>
<permission>hudson.model.Hudson.UploadPlugins:put-your-username</permission>
<permission>hudson.model.Item.Build:put-your-username</permission>
<permission>hudson.model.Item.Cancel:put-your-username</permission>
<permission>hudson.model.Item.Configure:put-your-username</permission>
<permission>hudson.model.Item.Create:put-your-username</permission>
<permission>hudson.model.Item.Delete:put-your-username</permission>
<permission>hudson.model.Item.Discover:put-your-username</permission>
<permission>hudson.model.Item.Read:put-your-username</permission>
<permission>hudson.model.Item.Workspace:put-your-username</permission>
<permission>hudson.model.Run.Delete:put-your-username</permission>
<permission>hudson.model.Run.Update:put-your-username</permission>
<permission>hudson.model.View.Configure:put-your-username</permission>
<permission>hudson.model.View.Create:put-your-username</permission>
<permission>hudson.model.View.Delete:put-your-username</permission>
<permission>hudson.model.View.Read:put-your-username</permission>
<permission>hudson.scm.SCM.Tag:put-your-username</permission>
Now, you can go to different directions. For example I had github oauth integration, so I could have tried to replace the authorizationStrategy with something like below:
Note:, It worked in my case because I had a specific github oauth plugin that was already configured. So it is more risky than the previous solution.
<authorizationStrategy class="org.jenkinsci.plugins.GithubAuthorizationStrategy" plugin="github-oauth#0.14">
<rootACL>
<organizationNameList class="linked-list">
<string></string>
</organizationNameList>
<adminUserNameList class="linked-list">
<string>put-your-username</string>
<string>username2</string>
<string>username3</string>
<string>username_4_etc_put_username_that_will_become_administrator</string>
</adminUserNameList>
<authenticatedUserReadPermission>true</authenticatedUserReadPermission>
<allowGithubWebHookPermission>false</allowGithubWebHookPermission>
<allowCcTrayPermission>false</allowCcTrayPermission>
<allowAnonymousReadPermission>false</allowAnonymousReadPermission>
</rootACL>
</authorizationStrategy>
Edit the file $JENKINS_HOME/config.xml and change de security configuration with this:
<authorizationStrategy class="hudson.security.AuthorizationStrategy$Unsecured"/>
After that restart Jenkins.
A lot of times you wont be having permissions to edit the config.xml file.
The simplest thing would be to take a back of config.xml and delete using sudo command.
Restart the jenkins using the command sudo /etc/init.d/jenkins restart
This will disable all the security in the Jenkins and the login option would disappear
For one who is using macOS, the new version just can be installed by homebrew. so for resting, this command line must be using:
brew services restart jenkins-lts
The directory where the file is located config.xml in windows
C:\Windows\System32\config\systemprofile\AppData\Local\Jenkins\.jenkins