root password is not working for su in terminal

Question

I'm using rhel 5, when i'm working in terminal first i typed su command and by mistake i entered copy command and some other characters, after realising i've made a mistake then i came out and continued with copy command in terminal.

after some time when i tried to login by using su and with password it says "incorrect password".

So i logged out and entered root login for gui and it works well, but i'm not able to use the same password for su.

can some one get around this issue?

Solution 1

Probably you have locked the root user by too many wrong authentications. Try

usermod -U root

to unlock the account.

Solution 2

I had the same problem and none of the above replies helped. In my case, I could login as root, sudo worked, but not su.

It turned out that /bin/su had somehow lost the suid permission.

I corrected that with chmod u+s /bin/su, and then su worked again.

Solution 3

Make sure the user trying to su is in the wheel group.

$ id uid=1000(usr) gid=1000(usr) groups=1000(usr),10(wheel),18(audio),19(cdrom),35(games),442(plugdev),1003(pulse-access)

if you don't see wheel, your su will fail.

Or you can edit the su file in the /etc/pam.d directory and modify it to not require wheel group to be able to escalate your privileges.

Comments

[Admin]

@Carlos Campderrós first i tried to login using su, after typing 'su' instead of password i typed copy command ,then realised i mad a mistake and came out of it after that i continued my work. but after some time i again tried to login using su, it says 'incorrect password'. but meanwhile i didn't changed any passwords...

[UselesssCat]

More than a complete hour trying to find this. I remember that i used chmod in the root folder changing the permission of all folders recursively :P, is a real miracle thats my debian stills working. thanks

[SL5net]

i have the same problem. linux mint just installed. how you fix that ? how you could do chmod u+s /bin/su without this rights?

[SL5net]

how you could do thsis without admin rights?

[ceving]

@SL5net You can't. Locking a account would not make much sense otherwise.

[SL5net]

i just now installed LinuxMint fresh. 3times. same problem. do i need than change linux disto?

[SL5net]

in the next attempt i used ubuntu. and didn't have this problem. the virtualbox extensions were even started automatically from the virtual cd.

[Salem F]

I was facing issue with sudo not with su, sudo were not accepting my password, but when I login as root with su root entering my password accepted it and I issued the command usermod -U root and sudo works now, BTW I had script I run often used sudo but I add it to NOPASSWD list in visudo