Wednesday, June 8, 2022

AWS EC2 - SSH locked with UFW

Need to update the instance's user data:

1. Stop the instance

2. Right click (windows) or ctrl + click (Mac) on the instance to open a context menu, then go to Instance Settings -> Edit User Data or select the instance and go to Actions -> Instance Settings -> Edit User Data

If you're still on the old AWS console, select the instance, go to Actions -> Instance Settings -> View/Change User Data

3. Past following in: 


ontent-Type: multipart/mixed; boundary="//"
MIME-Version: 1.0
--//
Content-Type: text/cloud-config; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="cloud-config.txt"
#cloud-config
cloud_final_modules:
- [scripts-user, always]
--//
Content-Type: text/x-shellscript; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="userdata.txt"
#!/bin/bash
ufw disable
iptables -L
iptables -F

--//


4. Once added, restart the instance and ssh should work. 

The user-data disables ufw if enabled and also flushes any iptable rules blocking ssh access.

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AWS EC2 - SSH locked with UFW

Need to update the instance's user data: 1. Stop the instance 2. Right click (windows) or ctrl + click (Mac) on the instance to open a c...