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Old 02-17-2005, 10:28 AM   #1
harken
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Registered: Jan 2005
Location: Between the chair and the desk
Distribution: Debian Sarge, kernel 2.6.13
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Strange root password problem


Please read all of it before flaming me about lost root passwords.

Actually it's not forgotten. Here's what happened: with the desire of improving my computer's security I started reading some materials on it. So, I came upon this article which said, among others, to create a "wheel" group, add the priviledged users to it, blah, blah. I already did that a while ago. Yet, it said to add "critical binaries" such as /bin/su to this group. Ok, so I did a 'chown root:wheel /bin/su'. At the moment I forgot about this but later, when I tried to su again...
Quote:
harken@vsoft:~$ su
Password:
su: Authentication failure
Sorry.
I said to myself maybe I forgot indeed the password so I picked up the Knoppix CD, chrooted to /bin/bash, passwd root...succesfully updated UNIX password. Booted back to Debian...the same thing. Knoppix once again...maybe I mistyped...same result.

On the other hand, if I boot into single mode or, even stranger, I use Ctrl-Alt-F1 to get to a shell prompt, the root password is working just fine. So the problem seems to come from su. Also, all the other programs that need root privileges such as Synaptic, QTParted, you name it, fail to run because "wrong password".

EDIT: at some point, one of the programs told me something that it couldn't read /etc/passwd (because I accidentaly hit the Cancel button). So, just out of curiosity I did a 'ls -l /etc/passwd' and...it told me its creation date would be 2005-02-19 ! The next time I booted it switched back all by herself to 02-17. Strange, isn't it?

Might be something obvious that I'm missing but what on Earth is wrong?
I appologize in advance if this is a stupid question and feel free to blame (I'll get over it)...just tell me the answer.

Last edited by harken; 02-17-2005 at 10:31 AM.
 
Old 02-17-2005, 10:56 AM   #2
harken
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Registered: Jan 2005
Location: Between the chair and the desk
Distribution: Debian Sarge, kernel 2.6.13
Posts: 666

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And something else: when I went in Knoppix to change root's password I noticed that /bin/su belonged to root:sslwrap (or sslwrp, I don't remember exactly). And changed the ownership back to root:root but no use.

Thanks in advance.

Update: I have another account name, with regular privileges, just in case. And the same thing happens: I can login with that name only from Ctrl-Alt-F1, and no other way.

Last edited by harken; 02-17-2005 at 11:00 AM.
 
Old 02-17-2005, 12:32 PM   #3
makuyl
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Registered: Dec 2004
Location: Helsinki
Distribution: Debian Sid
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Is /etc/passwd readable for all and do you have the suid bit set on /bin/su?
markus@fujibox:~$ ls -l /bin/su /etc/passwd
-rwsr-xr-x 1 root root 23416 Dec 23 23:40 /bin/su
-rw-r--r-- 1 root root 1605 Feb 7 14:15 /etc/passwd
 
Old 02-17-2005, 01:12 PM   #4
harken
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Registered: Jan 2005
Location: Between the chair and the desk
Distribution: Debian Sarge, kernel 2.6.13
Posts: 666

Original Poster
Rep: Reputation: 30
Duh...didn't noticed there's no 's' in permissions. Thanks, a 'chmod 4755 /bin/su' solved the problem.
Boy, can one be dumb at some time.
 
  


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