| 1 | <?xml version='1.0' encoding='UTF-8'?>
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| 2 | <!DOCTYPE topic PUBLIC "-//OASIS//DTD DITA Topic//EN" "topic.dtd">
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| 3 | <topic xml:lang="en-us" id="diskencryption-limitations">
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| 4 | <title>Limitations of Disk Encryption</title>
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| 5 |
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| 6 | <body>
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| 7 | <p>
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| 8 | There are some limitations the user needs to be aware of when
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| 9 | using this feature:
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| 10 | </p>
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| 11 | <ul>
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| 12 | <li>
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| 13 | <p>
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| 14 | This feature is part of the Oracle VM VirtualBox Extension Pack,
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| 15 | which needs to be installed. Otherwise disk encryption is
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| 16 | unavailable.
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| 17 | </p>
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| 18 | </li>
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| 19 | <li>
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| 20 | <p>
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| 21 | Since encryption works only on the stored user data, it is
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| 22 | currently not possible to check for metadata integrity of
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| 23 | the disk image. Attackers might destroy data by removing or
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| 24 | changing blocks of data in the image or change metadata
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| 25 | items such as the disk size.
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| 26 | </p>
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| 27 | </li>
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| 28 | <li>
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| 29 | <p>
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| 30 | Exporting appliances which contain encrypted disk images is
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| 31 | not possible because the OVF specification does not support
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| 32 | this. All images are therefore decrypted during export.
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| 33 | </p>
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| 34 | </li>
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| 35 | <li>
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| 36 | <p>
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| 37 | The DEK is kept in memory while the VM is running to be able
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| 38 | to decrypt data read and encrypt data written by the guest.
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| 39 | While this should be obvious the user needs to be aware of
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| 40 | this because an attacker might be able to extract the key on
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| 41 | a compromised host and decrypt the data.
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| 42 | </p>
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| 43 | </li>
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| 44 | <li>
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| 45 | <p>
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| 46 | When encrypting or decrypting the images, the password is
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| 47 | passed in clear text using the Oracle VM VirtualBox API. This
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| 48 | needs to be kept in mind, especially when using third party
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| 49 | API clients which make use of the webservice where the
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| 50 | password might be transmitted over the network. The use of
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| 51 | HTTPS is mandatory in such a case.
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| 52 | </p>
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| 53 | </li>
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| 54 | <li>
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| 55 | <p>
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| 56 | Encrypting images with differencing images is only possible
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| 57 | if there are no snapshots or a linear chain of snapshots.
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| 58 | This limitation may be addressed in a future Oracle VM VirtualBox
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| 59 | version.
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| 60 | </p>
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| 61 | </li>
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| 62 | <li>
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| 63 | <p>
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| 64 | The disk encryption feature can protect the content of the
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| 65 | disks configured for a VM only. It does not cover any other
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| 66 | data related to a VM, including saved state or the
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| 67 | configuration file itself.
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| 68 | </p>
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| 69 | </li>
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| 70 | </ul>
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| 71 | </body>
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| 72 |
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| 73 | </topic>
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