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Ibrar Hussain
Ibrar Hussain

Posted on Originally published at Medium

Resolving SSH Permission Denied Errors Due to OpenSSH Version Vulnerabilities

#openai #api #terminal #opensource

If you have encountered errors while using SSH, such as the ones below:

Example 1:

foo@12.34.56.789: Permission denied (publickey).
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Example 2:

sign_and_send_pubkey: no mutual signature supported
foo@12.34.56.789: Permission denied (publickey).
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It's possible that you may be using an older version of OpenSSH on your server that is vulnerable to the SHA-1 algorithm, which was disabled in OpenSSH version 8.8 (2021-09-26). If you're certain that you've correctly added the public key to your server, this could be the cause of the error messages.

To determine your local OpenSSH version, enter the following command:

ssh -vv local
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The result should look like this:

OpenSSH version

To resolve the issue, add PubkeyAcceptedKeyTypes +ssh-rsa to your Host entry in the ~/.ssh/config file. It should look like this:

Host fooServer
PubkeyAcceptedKeyTypes +ssh-rsa
Hostname 12.34.56.789
User forge
IdentityFile=~/.ssh/id_rsa
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After making these changes, try again and the issue should be resolved.

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