What are the default passwords of these users?
root
daemon
bin
sys
sync
games
man
lp
mail
news
uucp
nobody
Can anyone log in through ssh or ftp as these users?
what are default password of these users : root, daemon, bin, sys, sync, games, man, lp, mail, news, uucp, nobody.
You can check the status by looking in the shadow password file (/etc/shadow
) at the second field. By default these accounts are locked (the password is set to *
), which disables logins.
Can anyone login through ssh or ftp by these users ??
Not unless you have set a password for them.
man 5 passwd
;man login;man 3 crypt` )
Mar 11, 2014 at 17:05
If you would look at the password file you would see that these have a specific setting (games used as an example):
$ more /etc/passwd|grep games
games:x:5:60:games:/usr/games:/bin/sh
The 1st three (: is the separator):
The password is hashed (if it starts with a $ it is encrypted).
Regarding /etc/shadow
If the password field contains some string that is not a valid result of crypt(3), for instance ! or *, the user will not be able to use a unix password to log in (but the user may log in the system by other means).
Can anyone login through ssh or ftp by these users ??
Not by default. In theory you can create a user named games as an actual user or change the pwd of the user games.
games
account I have no problem logging in as games
.
Feb 27, 2014 at 11:50
/etc/shadow
, you'll see that these accounts do not have a password assigned at all, and are marked as locked from login. I think the wording of this answer could be improved.
Logins like nobody
will typically be "locked", so it is not possible to log in as them using a password (in any way, not SSH, not FTP, not the su
command etc)
http://manpages.ubuntu.com/manpages/hardy/man1/passwd.1.html
-l, --lock
Lock the named account. This option disables an account by changing
the password to a value which matches no possible encrypted value,
and by setting the account expiry field to 1.
However, if you have sudo access you can switch to these accounts with a command like this:
$ sudo su nobody
This is because the super-user can change to any account without entering a password
Most of this users are reserved for some service , you cannot log in with , the aim of this users is when its hacked it has minimal affect on your system like nobody user which has no password making it possible for attacker to know.
Ubuntu by default root account is locked for security issues , you can use sudo to have admin privileges and the password is unknown and encrypted .
In Addition ,
Some of these users are users having a valid shell with no password ( like bin )
It cannot connect by ssh because it needs /bin/.ssh/authorized_keys
to connect .
By other words these users are security users other than login based users .
Note its not recommended to change the state of these users ( change passwords or lock or unlock)