Host fingerprint verification fails

[markgomez]

I'm unable to get host fingerprint verification to succeed. The following works (i.e., my SSH settings are proven to be correct since the workflow completes):

jobs:
  build:
    name: Build
    runs-on: ubuntu-latest
    steps:
      - name: executing remote ssh commands using ssh key
        uses: appleboy/ssh-action@v1.0.0
        with:
          host: ${{ secrets.SSH_HOST }}
          username: ${{ secrets.SSH_USER }}
          key: ${{ secrets.SSH_KEY }}
          passphrase: ${{ secrets.SSH_PASSPHRASE }}
          script_stop: true
          script: # ...

But when I add my remote server's public fingerprint...

jobs:
  build:
    name: Build
    runs-on: ubuntu-latest
    steps:
      - name: executing remote ssh commands using ssh key
        uses: appleboy/ssh-action@v1.0.0
        with:
          host: ${{ secrets.SSH_HOST }}
+         fingerprint: ${{ secrets.SSH_HOST_FINGERPRINT }}
          username: ${{ secrets.SSH_USER }}
          key: ${{ secrets.SSH_KEY }}
          passphrase: ${{ secrets.SSH_PASSPHRASE }}
          script_stop: true
          script: # ...

...the workflow fails with the following message:

======END======
2023/10/17 02:28:35 ssh: handshake failed: ssh: host key fingerprint mismatch

I've triple-checked that I'm adding/saving the correct repo action secret, the output from the following command while logged into my remote server:

ssh-keygen -l -f /etc/ssh/ssh_host_ed25519_key.pub | cut -d ' ' -f2

I've also checked against the following command:

ssh-keyscan <my_ssh_host> | ssh-keygen -lf -

The fingerprints are consistent with each other, so I'm not sure what's causing the mismatch. Any additional debugging steps I should try? My remote server is running Ubuntu 22.04.3 LTS.

[msalehipro]

same problem

[csnyder616]

Also encountering this issue. Remote server for me is Debian 12, so probably similar configuration to Ubuntu. I tried just about every permutation I could think of, and both RSA and ed25519 keys.

[thinkovation]

I have the same problem - but it only occurrs when I add an SCP command...

With SCP command...

With SCP commented out...

Here's my workflow source..

`# Step 1 V5
name: Deploy Go Program

on:
push:
branches:
- main

jobs:
deploy:
runs-on: ubuntu-latest
steps:
- name: Checkout repository
uses: actions/checkout@v2
- name: Copy assets and binary to remote server
uses: appleboy/ssh-action@master
with:
host: ${{ secrets.SSH_HOST }}
username: ${{ secrets.SSH_USERNAME }}
key: ${{ secrets.SSH_PRIVATE_KEY }}
port: ${{ secrets.SSH_PORT }}
fingerprint: ${{ secrets.SSH_FINGERPRINT }}
script: |
# Remove existing binary and assets folder
ls ~/
rm -rf ~/test
mkdir -p ~/test
ls ~/test/
touch /test/foo.md
#scp -r test.md ${{ secrets.SSH_USERNAME }}@${{ secrets.SSH_HOST }}:/test
ls ~/test/`

[Jeff-Tian]

I met the same issue, and thanks, @thinkovation, for the inspiration! I fixed it by removing the fingerprint option, as, by default, it's not needed.

The thing is that my scripts contain git pull, which causes the ssh fingerprint issue. So it's not about GitHub Actions connecting to the server; it's about the server can't contact the Git Origin.

So, I logged into the server and fixed that.

No need to add the fingerprint to the GitHub Actions secret.

[METACEO]

I would appreciate knowing why this isn't working for me. I get the same issue in both appleboy/scp-action and appleboy/ssh-action.

I've tried following the docs with the ssh-keygen commands to print out the SHA256. I've tried a combination of the below, no luck.

Tried with the SHA256 prefix

SHA256:<hash here>

And tried without the SHA256 prefix

<hash here>

It'd be great to have some examples here for this extra security measure!

[kenjis]

The same problem.

======END======
2024/05/18 10:53:48 ssh: handshake failed: ssh: host key fingerprint mismatch

According to #81 (comment)
the correct format is just <hash algo>:<fingerprint> eg: SHA256:Bbf….
I tried it, but it does not work.

[Finn10111]

I tried all mentioned suggestions but same for me, it doesn't work...

[shehata412]

I had the same issue and was fixed when I SSH to the server and either git clone or git pull first so that I can save the fingerprint on the server, then I run my workflow.

Try that and let me know how it goes.

[codeAndxv]

I encountered the same issue. Below is my solution. First, it's important to know that there are three types of fingerprints. Please check the /etc/ssh directory on the remote server to see if it contains rsa, ecdsa, and ed25519 key.pub files. I first tried rsa and ed25519, and finally switched to the ecdsa fingerprint, which successfully passed the verification.

I'm not sure what rules GitHub Actions uses to choose the validation algorithm. To avoid potential issues, I didn't choose to delete the other two algorithms and only kept one.