SVR4 # 7
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FECO: |
SVR4 # 7 |
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MODIFICATION NO: |
N/A | |
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PRODUCT: |
SVR4 | |
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SUB-ASSEMBLY: |
N/A | |
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ESTIMATED MAN HOURS: |
N/A | |
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CLASS OF CHANGE: |
INFORMATIONAL | |
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REASON FOR CHANGE: |
LOST PASSWORD RECOVERY PROCEDURE | |
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RELATED FECO/AB |
N/A |
RECOVERING A LOST ROOT PASSWORD ON SVR4
1 NOTE:
Throughout this FECO a SPACE in a string is shown by a Ñ .
All other spaces are purely cosmetic
2 INTRODUCTION
If the root password is lost on an SVR4 system, then it is not possible to go into root to
shut the
system down
correctly.
3 PRE-REQUISITES
3.1 To
recover the root password on an SVR4 machine you will require all users to be off the
machine,
and to have
the maintenance media available.
3.2 You will need
to find out what disk, Unix has been installed on, to enable you to mount the filesystem
e.g.
/dev/dsk/c0t0d0s0.This should be in the onsite documentation.
3.3 You will have
to crash the machine, as without the root password you will not be able to reboot it, so
you must ensure
that all users are off the machine and the machine is as inactive as possible.
4 RECOVERING THE PASSWORD
4.1 Insert the maintainance cd in the drive and
Press the reset button or switch the system off then on.
When the system
reboots it will find Unix installed on the cd and boot from it and this will bring you
to the NCR installation
maintainance and restore facility menu.
NCR INSTALLATION MAINTENANCE AND RESTORE FACILITY
Select one of the following:
Type selection number, then press ENTER. [default = 1] > 2
4.2 Take option 2 ‘perform system
maintainance’, and the base operating system will be loaded and
you will
get to a # prompt. As the system has not been cleanly shutdown you will have to perform
an fsck to check
the filesystem as it will have a flag advising it was not shutdown properly and
cannot be
mounted. The syntax is:-
fsck Ñ –F Ñ vxfs Ñ / dev / dsk / (root slice)
e.g. fsck Ñ –F Ñ vxfs Ñ / dev / dsk / c0t0d0s1
4.3 You will get messages advising that the superblock is
clean if the fsck is successful. You will then
need to mount the root
partition of the disk. The syntax is:-
mount Ñ –F Ñ vxfs Ñ / dev / dsk / (root slice) Ñ / (mount point)
e.g. mount Ñ –F Ñ vxfs Ñ / dev / dsk / c0t0d0s1 Ñ / mnt
This will mount the vxfs root filesystem at a mount point of /mnt.
4.4 The next step is to remove the encrypted password from the /mnt/etc/shadow file.
e.g. vi Ñ / mnt / etc / shadow
root:hrAF6n7J0JYqU:11367:0:168:7:::
4.5 Move the cursor to the first letter
after the initial colon using the arrow keys and then press ‘x’ to delete
each character until you reach the second
colon.
Then press ‘esc’ and then type ‘:wq!’ to write away the file.
You can then page the file and the root entry should look similar to the following:-
root::11367:0:168:7:::
4.6 The other file to be amended is the /mnt/etc/passwd file. You
need to remove the ‘x’ between the first
two colons on the line that starts with
root and then file away the file.
e.g. vi mnt / etc / passwd
root:x:0:1:0000-Admin(0000):/:
4.7 Move the cursor over the top of the x character using the arrow
keys and then press ‘x’ to delete the
character, then press ‘esc’ and then type
‘:wq!’ to write away the file. You can then page the file and
the root entry should look similar to the
following:-
root::0:1:0000-Admin(0000):/:
4.8 You can then change directory back to root ‘ cd /’ and unmount the root filesystem ‘umount /mnt’.
4.9 The system can then be rebooted and you can login as root and it will
prompt you to enter a new
password as the old one has expired.