March 2015 – La Fabulosa Vida de un IT

Sometimes when a business decide to switch his computer maintenance to another company switched company rejects to give server passwords with or without good reason.

There’s a lot of ways of reset administrator password, but recover any of then can be better.

If you need to recover passwords from a windows 2003 server a easy way is shutdown the server and start a linux live CD like ubuntu.

If you can access to windows filesystem you can access to SAM data, a database with local passwords 😛 .

You only need to copy %SystemRoot%/system32/config directory to a flash memory or another storage device.

Install into another computer Ophcrack software. In my laptop running fedora 21 executeas root

dnf install ophcrack

Download XP rainbow tables from here http://ophcrack.sourceforge.net/tables.php

Open ophcrack

Click on Tables -> install

and load downloaded tables

Now at load button select Encrypted SAM and open the folder %SystemRoot%/system32/config recovered using Linux liveCD

and finally click on Crack button

Only took half minute, literally in recover 13 of 14 passwords.

Enjoy

Sometimes hardware Raid controllers are very expensive to fit in low budget solutions, when this happens you can use software raid, like mdadm.

Normally hard disks have a limited lifetime. To avoid disasters I replace hard disk every two years, at same time that means that new hard disk will come in a bigger capacity. I will simulate this workflow.

Unfortunately I’m not a rich engineer yet and need to simulate hard disk, if you want to donate some hard disk leave me a comment 🙂

step 1 and 2 are for create virtual hard disk,

REMEMBER MAKE BACKUPS BEFORE DO DANGEROUS THINGS LIKE THESE

Step 1: Create virtual hard disk

Imagine that in a beginning we have a couple of two hard disk with a capacity of one terabyte (1HD and 2HD), and after two years we acquired two new hard drives with a capacity of three terabyte (3HD and 4HD).

I will use gigabytes instead terabytes for time and capacity reasons

as root

cd
mkdir mdadmtesting
cd mdadmtesting
fallocate -l 1G 1HD.raw
fallocate -l 1G 2HD.raw
fallocate -l 3G 3HD.raw
fallocate -l 3G 4HD.raw

Step 2: Associate created files with loop devices

losetup /dev/loop0 /root/mdadmtesting/1HD.raw
losetup /dev/loop1 /root/mdadmtesting/2HD.raw
losetup /dev/loop2 /root/mdadmtesting/3HD.raw
losetup /dev/loop3 /root/mdadmtesting/4HD.raw

Step3: create a mdadm device in raid 1 mode

mdadm –create –verbose /dev/md0 –level=1 –raid-devices=2 /dev/loop0 /dev/loop1
mkfs.ext4 /dev/md0

finally we need to mount new raid and make some files

mount /dev/md0 /mnt
cd /mnt
for i in {1..100}; do echo $i > $i; done

Step 4 Replace one hard disk

we need to mark one hard disk as fail to replace

mdadm –manage /dev/md0 –fail /dev/loop0

remove disk from array

mdadm –manage /dev/md0 –remove /dev/loop0

attach new hard disk

mdadm –manage /dev/md0 –add /dev/loop2

check raid status and wait until raid state is setted as clear and not

State : clean, degraded, recovering

mdadm –detail /dev/md0

Step 5: Replace second hard disk

mdadm –manage /dev/md0 –fail /dev/loop1
mdadm –manage /dev/md0 –remove /dev/loop1
mdadm –manage /dev/md0 –add /dev/loop3

wait until state is clean

mdadm –detail /dev/md0

Step 6 Grow raid device

At this moment we have removed our old 1Tb disk and they have been replaced with a new 3Tb drive but our raid size is 1Tb we need to grow it

mdadm –grow /dev/md0 –size=max

Step 7 Grow filesystem

Our raid size is 3Tb but our file system is still at 1Tb we need to resize it

resize2fs /dev/md0

and finally we have our mdadm raid with new drives and a lot of free space.