Monday, April 21, 2008

Unbreakable Security

The security feature supported in hard disk is unbreakable. Nobody can apply bruteforce/dictionary attack on your locked hard disk because

  1. First of all one don't have low level utility to give unlocking commands to hard disk.
  2. Even if one got the utility and do the bruteforce/dictionary attack, will get mad because at every sixth attempt hard disk needs to be applied hard reset. Security unlock command will be aborted if five wrong attempts are committed. After that, giving security unlock command results in command aborted until hard reset.
  3. Maximum password length can be as long as 32 characters.
  4. It has two security levels, high and maximum. And two password types, user password and master password.



  1. It can be done IF you don't care about the content of the hdd and it is in HIGH mode since the attempts to format/erase the device with the master password are NOT limited...

  2. Hi anonymous,

    Thanks for your comment.

    I have not tried SECURITY ERASE PREPARE/UNIT commands, so don't know how unlock counter works on these commands.
    But ATA spec. says "When the security level is set to High the device requires the SECURITY UNLOCK command and the Master password to unlock. When the security level is set to Maximum the device requires a SECURITY ERASE PREPARE command and a SECURITY ERASE UNIT command with the masterpassword to unlock". So, I doubt that in High Security Level whether you will be able to unlock using SECURITY ERASE PREPARE/UNIT commands.

    Also, I haven't verified that whether unlock counter doesn't get updated on SECURITY ERASE PREPARE/UNIT command. It might get updated on those command also. Because spec doesn't say that this counter is not updated on SECURITY ERASE PREPARE/UNIT command.

    These are just my thoughts. Again, I haven't tried SECURITY ERASE PREPARE/UNIT commands, so not 100% sure about this.

    Let me know if you have verified it.

  3. Hi,

    Great Job Sandeep for your ata-util program. Listen, I have locked a laptop hard drive by mistake. I got an adapter to read the hard drive laptop on a normal computer and I think I can try unlimited password try to unlock it without resseting it, because it is a laptop hard drive. But I need a modified version of ata-util or the source code to unlock it.

    I am sure there is many other people with the same problem and if you could help me, it will also help others.


  4. Hi Guillaume,

    What changes you require in ata-util?
    I will try to add them if it is possible.

    Sandeep Vaniya

  5. Hi Sandeep,

    Finally, I tested again to unlock the laptop hard drive and it actually only accept few passwords in a row and after that I need to unplug the power and plug it back for the count to reset. So, the brute force method I was thinking would not work. Thanks anyway for your fast response.


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