How Amazon AWS does sudo not need a password

2017-05-29

I have used many service providers, including AWS. In many service providers, the host needs a password, but AWS does not. AWS is a certificate login. However, after other service providers log on, sudo needs a password, while aws does not, which surprised me. After a series of explorations, I found the difference between AWS and other service providers.

This article was migrated from My Own. The original link is https://wudew.com/posts/63

stay /etc/sudoers There is such a line

 # includedir /etc/sudoers. d

This line refers to /etc/sudoers. d Below (basically) all documents (refer to /etc/sudoers.d/README ）

Then amazon installer creates /etc/sudoers.d/90-cloud-init-users Such a file has the following contents

 # Created by cloud-init v. 0.7.5 on Sat, 14 May 2016 12:31:57 +0000

 # User rules for ubuntu ubuntu ALL =(ALL) NOPASSWD:ALL

It seems that the result is obvious, /etc/sudoers It refers to the files of users who do not need passwords in sudo. Because of security, ubuntu does not recommend modifying them directly /etc/sudoers Files, but contains /etc/sudoers. d Directory. By creating a permission file in this directory, the password sudo is not required In addition, this is the file information of 90 cloud init users: -r--r----- 1 root root 123 May 14 2016 90-cloud-init-users