ec2-user is not able to do sudo - Linux + AWS

ec2-user is not able to do become root user:

ec2-user is not able to do sudo or ec2-user is not able become root user.

I was getting below error when I logged in as ec2-user with the .ppk file and then I was trying to become root user by using #sudo –i

[ec2-user@cloud_home]# sudo : effective uid is not 0, is sudo installed setuid root ?

While doing initial troubleshooting, we got to know that someone has changed the /usr/bin/sudo file permission accidentally. [But even he was unaware about that]

Answer :

1.      Login to AWS console and stop the instance

2.      Detach the root disk (/dev/sda1)

3.      Attach it to any running server [who are in same availability zone] as data disk [/dev/xvdg – device name of the disk given by AWS at the time of attaching it]

4.      Start the Instance from AWS console

5.      mount the disk on OS

[root@cloud_home2]# mount /dev/xvdg2 -o no-uuid /mnt ; cd  /mnt ; ls -l usr/bin/sudo

6.      Change permission of /usr/bin/sudo

[root@cloud_home2]# chmod u+s /mnt/usr/bin/sudo ; ls -l usr/bin/sudo

7.      Un-mount temporary mount point

[root@cloud_home2]# umount /mnt

8.      Detach the disk from this server
9.      And re-attach to original server as root disk where we are getting problem.

10. Start instance

11. Login with ec2-user

12. Now try to do sudo and this time you will be able to it.

[ec2-user@cloud_home]# sudo –i
[root@cloud_home]#

Regards,

Kirraan Jadhav