Consider the following Linux system:
- root account is disabled (
passwd -l root,
passwd -d root),
- there is an account 'admin', with sudo rights,
- there is an account 'webservice', with limited privileges, and no sudo rights,
suis disabled via PAM (
auth required pam_wheel.so),
- only 'admin' can SSH into the system (
AllowUsersdirective, only with a key, no password accepted),
- 'webservice' runs some web services which has been compromised: an attacker can now run remotely any shell command as the user 'webservice',
- the attacker has no physical access to the device,
- finally, the attacker knows the 'admin' password, but not admin's SSH key
How could the attacker run a command as 'admin'?
My understanding is that the attacker cannot sudo, cannot su, cannot SSH, even if the admin password is known, so no privilege escalation is possible. Is that correct? My objective is to understand the consequences and the possible mitigation (if any) of having an admin password compromised.