CODEWITHSUNDEEP
gossh
Derek
Derek

Reputation: 367

Connecting to a Cisco Switch with crypto/ssh

I am using this code https://gist.github.com/svett/b7f56afc966a6b6ac2fc as a starting point.

Using it and pointing it to a cisco router gets me the following error message:

Failed to dial: ssh: handshake failed: ssh: no common algorithm for client to server cipher; client offered: [aes128-ctr aes192-ctr aes256-ctr [email protected] arcfour256 arcfour128], server offered: [aes128-cbc 3des-cbc aes192-cbc aes256-cbc]

After doing some reading, I learned that I could enable aes128-cbc by customizing the config: 

// CBC mode is insecure and so is not included in the default config.
// (See http://www.isg.rhul.ac.uk/~kp/SandPfinal.pdf). If absolutely
// needed, it's possible to specify a custom Config to enable it.

So I added : 

HostKeyAlgorithms: []string{"aes128cbcID"},

to my ssh.ClientConfig and I got a different error:

Failed to dial: ssh: handshake failed: ssh: no common algorithm for host key; client offered: [aes128cbcID], server offered: [ssh-rsa]

This basically makes me think I'm specifying the HostKeyAlgorithm when I need to specify the client to server cipher, but I cannot find my way around well enough to figure out how to do so.

Any ideas?

Upvotes: 5

Views: 1488

Answers (1)

Mr_Pink
Mr_Pink

Reputation: 109442

What you want is to set the Ciphers field in the client's config. It's in the common ssh.Config struct, embedded in the ssh.ClientConfig

sshConfig.Ciphers = []string{"aes128-cbc"}

Upvotes: 7

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