I'm trying to give access to a GCE VM by adding SSH Keys to the project metadata. My current SSH key is in the project metadata and I can connect just fine using:
ssh -i ~/.ssh/<private_key> <username>#<instance_ip>
Now, I generated another key:
ssh-keygen -t rsa -f ~/.ssh/<new_key> -C <new_username>
After adding the generated public key to the project metadata, I then run:
ssh -i ~/.ssh/<new_private_key> <new_username>#<instance_ip>
But I get Permission denied (publickey,gssapi-keyex,gssapi-with-mic). Running with -vvv flag doesn't show me much besides the key being rejected.
Things I know/checked:
firewall isn't an issue because I can connect using my original key from same location
the instance is running SSH (running nc <instance_nat_ip> 22 shows "OpenSSH" etc.)
no passphrases were used with the generation of any SSH key
there are no instance-level restrictions on project-wide metadata
there are no instance-level ssh keys already added
there are no newlines/breaks causing the key to be malformed
permissions on ~./ssh aren't an issue since another key pair works fine from the same directory, additionally, both key pairs have the same permissions anyways
OSLogin isn't enabled either on the project or instance
Things I've tried:
removing and readding the SSH keys in project metadata
trying with new key pairs generate on another person's machine
restarting sshd service
Questions:
Does the username specified during the ssh-keygen step have to already exist on the remote instance prior to adding the key to the metadata? i.e. do I have to run sudo useradd <new_username> while SSH'd into the instance Creating a new test instance revealed this to not be the case, all users in the project metadata were created automatically
why does my existing SSH key work and not new ones even though they are added the same way?
there's a chance the enable-oslogin:TRUE was applied to the instance briefly a long time ago (I'm not sure since I'm not the one who created the instance) but it's no longer there in the instance or project metadata. Would having that been enabled, even briefly, cause some issues?
EDIT: I started up a new instance in the same project with the same network details and I was able to SSH to that instance using the new key. Original instance is still denying the key
Did some digging around and found out that the systemd service that propagates accounts information from the metadata server is a daemon called google-accounts-daemon.
When I ran sudo ps aux | grep daemon I didn't see it running as I did on the test instance I created.
So when I ran sudo systemctl restart google-accounts-daemon the SSH keys magically propagated and everything worked.
I have no idea what caused the daemon to stop running in the first place, so if anyone has ideas, that'd be appreciated in case this comes up in the future.
thank you for your time.
I have an EC2 instance, but for security reasons i need to change the pem files associated in .ssh/authorized_keys. I do understand that the public pem file goes into authorized_keys.
I do not want to mount the volume of the ec2 instance to a new one. I am considering as a last option since I do have access to the EC2 instance.
How can this be done?
I have tried:
This post Change key pair for ec2 instance the answer by Pat Mcb, but no luck.
Run this command after you download your AWS pem.
ssh-keygen -f YOURKEY.pem -y Then dump the output into
authorized_keys.
Or copy pem file to your AWS instance and execute following commands
chmod 600 YOURKEY.pem and then
ssh-keygen -f YOURKEY.pem -y >> ~/.ssh/authorized_keys
But that didn't work for me. If i follow it exactly download aws key pair key, and follow the instructions by coping the key when ssh into the instance, when i do ssh-keygen -f YOURKEY.pem -y >> ~/.ssh/authorized_keys It asks for a passphrase (never had to input one)
What i am doing is the following.
I create a new key with
ssh-keygen newpem.pem
and the .pub file i copy it in .ssh/authorized_keys
Can someone explain what i am doing incorrectly?
Note the authorized_keys file has the correct permissions.
Seems like you want to deprecate the old key and use a new key instead. These steps may help you -
Create a new key pair using the aws console and download it onto your system.
Retrieve the public key from the private key(.pem) file using the command - "ssh-keygen -y"
SSH into the instance using the old key.
Once you have access to the instance add the public key you got in step 2 into the "~/.ssh/authorized_keys" files and then save the file.
Log out of the instance and then try accessing the instance with the new key.
Hope it helps. Thank You !
You Don't even need to do all of this just mind few things with AWS EC2 you get a private key for default users . like ec2-user /ubuntu etc.
You are doing the right step
ssh-keygen -t rsa -C "your_email#example.com"
if it ask for entering any paraphrase leave it blank.
Just press to accept the default location and file name. If the .ssh directory doesn't exist, the system creates one for you.
Enter, and re-enter, if passphrase prompted
you have that key now .
Copy that key
Login to your Ec2 server.
sudo su
vim ~/.ssh/authorized_keys
paste the key.
:wq!
You'll see a key there copy it and save it as a backup somewhere.
Now paste your newly generated key in that file
and save the file.
now final step to take care is the permission, so run the following command.
sudo chmod 700 .ssh && chmod 600 .ssh/authorized_keys
Now you're good to go you.
Following are the steps to change your keypair on AWS EC2.
Login to AWS Console. Go to the Network and Security >> Keypair.
Give the name of your keypair (mykeypair) and keytype (RSA) and Private
keyformat (.pem). and click on the create keypair. It will ask you to
download .pem file in your local machine. Save it at and remember the
location.
Login to your EC2 instance and go to the .ssh. location. Create a new file called
(mykeypair.pem) and paste the content from the file we downloaded in step no.2
Run the command: sudo chmod 600 mykeypair.pem
Run the command: ssh-keygen -f mykeypair.pem -y and it will generate some
content. Copy that content. Open the file called autherized_keys and
remove all the content from it.
Paste the copied content that we have generated in the previous step. Also enter your file name (mykeypair) in last after entering space.
Reboot your instance. Go to the puttygen and generate the .ppk file
using the pem file you have downloaded from the keypair. You will be able to login your ec2 with the newly generated .ppk from putty.
Okay I figured out my problem. First of all I had been hacked by a hacker apparently because I didn't know that permitpasswordlogin: yes DISABLES pubkey authentication.... I thought it was additional security. So i used a very loose password that could be easily guessed. Anyways, I believe this because I went to the root folder and found that there was actually a new key in the root named "el patrono 1337" which actually means "the master/boss" in spanish... LOL. Anyways... So i changed that back to my secure key (made a new one actually) and then I went to login as ec2-user and couldnt, but could as root. was driving me crazy for 30 minutes or so until I realized I had accidentally changed the owner of my ec2-user folder to root and therefore ssh was not searching the ec2-user .ssh/authorized_keys when I tried to log in. Wow very glad that's over lol. And just fyi guys I don't think the hacker installed anything malicious, but I did get tipped off that he tried to ssh into other people's servers (who claim they get attacked by ssh alot according to the aws abuse report) from my machine. I'm running a very simple website with zero sensitive data etc. He didn't even block me out of the machine by disabling password authentication.(i guess he didn't want me to know?). I will build a new instance from scratch next time I want to add anything(will be pretty soon) just to be on the safe side.
I'm totally new using SaltStack and AWS, probably this is a dumb question, I created an AMI (using packer) with SaltStack (masterless) as a provisioner... I was able to connect via ssh and make a configuration to the minion. I was able to run salt-call state.highstate successfully.
Later, I lost the connection to my instance,
([root#<ip> ec2-user]# Write failed: Broken pipe) and after that, I wasn't able to connect again.
What's been tried:
Reboot the instance and didn't work
I've checked the permissions on the .ssh files and they seem fine
Create a new instance and use the same key.pem and I was able to connect to this new instance.
I'm not sure if I'm missing a configuration in SaltStack. Is there a possibility that the keys on my instance changed after running salt-call state.highstate ??
What am I doing wrong?
There's nothing inherent in running highstate that would have terminated the SSH connection and prevented you from reconnecting. I would suspect it's something in your SLS files which is breaking SSH - which is applied when you run highstate.
Things that might have been done by your Salt states:
your SSH keys were removed/mangled
opensshd config was changed
openssh-server was uninstalled
EDIT: Having seen the output from Salt in the pastebin linked in comments, it's probably the AuthorizedKeysFile option being commented out:
-AuthorizedKeysFile .ssh/authorized_keys
+#AuthorizedKeysFile .ssh/authorized_keys
I recommend using file.replace to patch in specific changes you need, as opposed to replacing the whole /etc/ssh/sshd_config with a new version.
I've created a new linux instance on Amazon EC2, and as part of that downloaded the .pem file to allow me to SSH in.
When I tried to ssh with:
ssh -i myfile.pem <public dns>
I got:
###########################################################
# WARNING: UNPROTECTED PRIVATE KEY FILE! #
###########################################################
Permissions 0644 for 'amazonec2.pem' are too open.
It is recommended that your private key files are NOT accessible by others.
This private key will be ignored.
bad permissions: ignore key: amazonec2.pem
Permission denied (publickey).
Following this post I tried to chmod +600 the .pem file, but now when I ssh I just get
Permission denied (publickey).
What school-boy error am I making here?
The .pem file is in my home folder (in macOS). Its permissions look like this:
-rw-------# 1 mattroberts staff 1696 19 Nov 11:20 amazonec2.pem
The problem is a wrong set of permissions on the file.
It is easily solved by executing: chmod 400 mykey.pem
This solution is taken from AWS instructions:
Your key file must not be publicly viewable for SSH to work. Use this command if needed: chmod 400 mykey.pem
400 protects it by making it read only and only for the owner.
You are likely using the wrong username to login, because—
Most Ubuntu images have a user ubuntu
Amazon's AMI is ec2-user
Most Debian images have either root or admin
To login, you need to adjust your ssh command:
ssh -l USERNAME_HERE -i .ssh/yourkey.pem public-ec2-host
I know this is very late to the game ... but this always works for me:
##step 1
ssh-add ~/.ssh/KEY_PAIR_NAME.pem
##step 2, simply ssh in :)
ssh user_name#<instance public dns/ip>
e.g.
ssh ec2-user#ec2-198-51-100-1.compute-1.amazonaws.com
Ok man, the only thing that worked for me was:
Change permissions of the key
chmod 400 mykey.pem
Make sure to log in using ec2-user, and the correct ec2-99... address. The ec2-99 address is at the bottom of the aws console when you're logged in and seeing your instance listed
ssh -i mykey.pem ec2-user#ec2-99-99-99-99.compute-1.amazonaws.com
Take a look at this article. You do not use the public DNS but rather the form
ssh -i your.pem root#ec2-XXX-XXX-XXX-XXX.z-2.compute-1.amazonaws.com
where the name is visible on your AMI panel
In windows you can go to the properties of the pem file, and go to the security tab, then to advance button.
remove inheritance and all the permissions. then grant yourself the full control. after all SSL will not give you the same error again.
Change permission for the key file with :
chmod 400 key-file-name.pem
See AWS documentation for connecting to the instance: Tutorial: Get started with Amazon EC2 Linux instances
I know this question has been answered already but for those that have tried them all and you are still getting the annoying "Permission denied (publickey)". Try running your command with SUDO. Of course this is a temporary solution and you should set permissions correctly but at least that will let you identify that your current user is not running with the privileges you need (as you assumed)
sudo ssh -i amazonec2.pem ec2-xxx-xxx-xxx-xxx.us-west-2.compute.amazonaws.com
Once you do this you'll get a message like this:
Please login as the user "ec2-user" rather than the user "root"
Which is also sparsely documented. In that case just do this:
sudo ssh -i amazonec2.pem ec2-xxx-xxx-xxx-xxx.us-west-2.compute.amazonaws.com -l ec2-user
And you'll get the glorious:
__| __|_ )
_| ( / Amazon Linux AMI
___|\___|___|
Feb, 2022 Update:
See the description to ssh to EC2 instance on AWS:
Then, you can find "No.3" saying this below:
So, run the command below as "No.3" says above:
chmod 400 myKey.pem
In Mac terminal, doing "chmod 400 xyz.pem" did not help me, it kept saying permission denied. For ubuntu users I would suggest
ssh-add xyz.pem
ssh -i xyz.pem ubuntu#ec2-54-69-172-118.us-west-2.compute.amazonaws.com (notice the user is ubuntu)
ssh -i /.pem user#host-machine-IP
I think it's because either you have entered wrong credentials
or, you are using a public key rather than private key
or, your port permissions are open for ALL to ssh. This is bad for Amazon.
There can be three reasons behind this error.
Your are using a wrong key.
Your key doesn't have the correct permissions. You need to chmod it to 400.
You are using the wrong user. Ubuntu images have a user ubuntu, Amazon's AMI is ec2-user and debian images have either root or admin
In addition to the other answers, here is what I did in order for this to work:
Copy the key to .ssh folder if you still hadn't:
cp key.pem ~/.ssh/key.pem
Give the proper permissions to the key
chmod 400 ~/.ssh/key.pem
Start ssh-agent (Thanks to https://stackoverflow.com/a/17848593 )
eval `ssh-agent -s`
ssh-add
Then, add the key
ssh-add ~/.ssh/key.pem
Now you should be able to ssh EC2 (:
SSH keys and file permission best practices:
.ssh directory - 0700 (only by owner)
private key/.pem file - 0400 (read only by owner)
public key/.pub file - 0600 (read & write only by owner)
chmod XXXX file/directory
Alternative log-in using PuTTY. Its good but needs a few steps.
Get your .pem that was generated when you first made the EC2 instance.
Convert the .pem file .ppk using PuttyGen since PuTTY does not read .pem.
Open PuTTY and enter your Host Name which is your instance username + Public DNS (Ex. ubuntu#ec2-xxx-xxx-xxx-xxx.region.compute.amazonaws.com). Not your AWS account username.
Then navigate to Connection > SSH > Auth. Then add your .ppk file. Click on Browse where it says "Private key file for authentication".
Click Open and you should be able to immediately establish connection.
Im using PuTTY 0.66 in Windows.
By default whenever you download the keyfile it come with 644 permissions.
So you need to change the permission each time you download new keys.
chmod 400 my_file.pem
In Windows go to the .pem file, right click and select Properties.
Go to Advanced in Security tab
Disable and remove inheritance.
Then press Add and select a principal.
Add account username as object name and press ok.
Give all permission.
Apply and save changes.
Now check the above command
You can find the answer from the ASW guide.
400 protects it by making it read only and only for the owner.
chmod 400 mykey.pem
In windows,
Right click on the pem file. Then select properties.
Select security tab --> Click on the Advanced button --> Disable inheritance --> Remove all inherited permissions from this object
Click on the Add button --> Select a principal --> Enter your username on the inputbox --> Click on the Check Names button --> Click on Ok --> Click on Ok --> Click on Ok --> Click on Ok
Do a chmod 400 yourkeyfile.pem
If your instance is Amazon linux then use ssh -i yourkeyfile.pem ec2-user#ip
for ubuntu
ssh -i yourkeyfile.pem ubuntu#ip
for centos
ssh -i yourkeyfile.pem centos#ip
Just change the permission of pem file to 0600 allowing only for the allowed user and it will work like charm.
sudo chmod 0600 myfile.pem
And then try to ssh it will work perfectly.
ssh -i myfile.pem <<ssh_user>>#<<server>>
BY default permission are not allowing the pem key.
You just have to change the permission:
chmod 400 xyz.pem
and if ubuntu instance then connect using:
ssh -i xyz.pem ubuntu#ec2-youraws.amazonaws.com
The issue for me was that my .pem file was in one of my NTFS partitions. I moved it to my linux partition (ext4).
Gave required permissions by running:
chmod 400 my_file.pem
And it worked.
I have seen two reasons behind this issue
1) access key does not have the right permission. pem keys with default permission are not allowed to make a secure connection. You just have to change the permission:
chmod 400 xyz.pem
2) Also check whether you have logged-in with proper user credentials. Otherwise, use sudo while connecting
sudo ssh -i {keyfile} ec2-user#{ip address of remote host}
Well, looking at your post description I feel there were 2 mistakes done by you:-
Set correct permissions for the private key.
Below command should help you to set correct file permision.
chmod 0600 mykey.pem
Wrong ec2 user you are trying to login.
Looking at your debug log I think you have spawned an Amazon linux instance. The default user for that instance type is ec2-user . If the instance would have been ubuntu then your default user would have been ubuntu .
ssh -i privatekey.pem default_ssh_user#server_ip
Note:
For an Amazon Linux AMI, the default user name is ec2-user.
For a Centos AMI, the default user name is centos.
For a Debian AMI, the default user name is admin or root.
For a Fedora AMI, the default user name is ec2-user or fedora.
For a RHEL AMI, the default user name is ec2-user or root.
For a SUSE AMI, the default user name is ec2-user or root.
For an Ubuntu AMI, the default user name is ubuntu.
Otherwise, if ec2-user and root don't work, check with the AMI provider.
source: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AccessingInstancesLinux.html
Key file should not be publicly viewable so use permission 400
chmod 400 keyfile.pem
If above command shows permission error use
sudo chmod 400 keyfile.pem
Now ssh into the ec2 machine, if you still face the issue, use ec2-user
ssh -i keyfile.pem ec2-user#ec2-12-34-56-78.compute-1.amazonaws.com
You're not in root then run this command
sudo chmod 400 -R myfile.pem
Not is root then run this command
chmod 400 -R myfile.pem
If you are connecting from Windows, perform the following steps on your local computer.
Navigate to your .pem file.
Right-click on the .pem file and select Properties.
Choose the Security tab.
Select Advanced.
Verify that you are the owner of the file. If not, change the owner to your username.
Select Disable inheritance and Remove all inherited permissions from this object.
Select Add, Select a principal, enter your username, and select OK.
From the Permission Entry window, grant Read permissions and select OK.
Click Apply to ensure all settings are saved.
Select OK to close the Advanced Security Settings window.
Select OK to close the Properties window.
You should be able to connect to your Linux instance from Windows via SSH.
From a Windows command prompt, run the following commands.
Run the following command to reset and remove explicit permissions:
icacls.exe $path /reset
Run the following command to grant Read permissions to the current user: icacls.exe $path /GRANT:R "$($env:USERNAME):(R)"
Run the following command to disable inheritance and remove inherited permissions : icacls.exe $path /inheritance:r
You should be able to connect to your Linux instance from Windows via SSH.
It is just a permission issue with your aws pem key.
Just change the permission of pem key to 400 using below command.
chmod 400 pemkeyname.pem
If you don't have permission to change the permission of a file you can use sudo like below command.
sudo chmod 400 pemkeyname.pem
Else if nothing works for you just follow this video to change the keys on your EC2 instance. You can install now public / private key pair on your instance.
https://youtu.be/LvLlRCrS8B4
Checklist:
Are you using the right private key .pem file?
Are its permissions set correctly? (My Amazon-brand AMIs work with 644, but Red hat must be at least 600 or 400. Don't know about Ubuntu.)
Are you using the right username in your ssh line? Amazon-branded = "ec2-user", Red Hat = "root", Ubuntu = "ubuntu". User can be specified as "ssh -i pem usename#hostname" OR "ssh -l username -i pem hostname"