Vista business efs

After you apply this hotfix, you have to enable it. To have us enable the hotfix for you, go to the "Fix it for me" section. If you would rather do this yourself, go to the "Let me fix it myself" section. To enable this hotfix automatically, click the Fix this problem link.

Then click Run in the File Download dialog box, and follow the steps in this wizard. Note This wizard may be in English only; however, the automatic fix also works for other language versions of Windows. Note If you are not on the computer that has the problem, you can save the automatic fix to a flash drive or to a CD, and then you can run it on the computer that has the problem. Now go to the "Did this fix the problem? Important This section, method, or task contains steps that tell you how to modify the registry.

However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully.

For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:.

On the Edit menu, click Modify , type 1, and then click OK. Check whether the problem is fixed. If it is fixed, you are finished with this article. If it is not fixed, you can contact support. The English version of this hotfix has the file attributes or later file attributes that are listed in the following table. When you view the file information, it is converted to local time.

Windows XP SP2, xbased versions. The security catalog files attributes not listed are signed with a Microsoft digital signature. For all supported xbased versions of Windows Server and of Windows Vista. Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. For more information, click the following article number to view the article in the Microsoft Knowledge Base:.

Need more help? Expand your skills. Get new features first. Was this information helpful? Yes No. Thank you! Any more feedback? The more you tell us the more we can help. Can you help us improve? Resolved my issue. This is because the backup of the user's RSA private key is encrypted with an LSA secret, which is accessible to any attacker who can elevate their login to LocalSystem again, trivial given numerous tools on the Internet.

In Windows XP and beyond, the user's RSA private key is backed up using an offline public key whose matching private key is stored in one of two places: the password reset disk if Windows XP is not a member of a domain or in the Active Directory if Windows XP is a member of a domain.

This means that an attacker who can authenticate to Windows XP as LocalSystem still does not have access to a decryption key stored on the PC's hard drive. In Windows , XP or later, the user's RSA private key is encrypted using a hash of the user's NTLM password hash plus the user name - use of a salted hash makes it extremely difficult to reverse the process and recover the private key without knowing the user's passphrase.

Also, again, setting Syskey to mode 2 or 3 Syskey typed in during bootup or stored on a floppy disk will mitigate this attack, since the local user's password hash will be stored encrypted in the SAM file. Windows can store versions of user account passphrases with reversible encryption, though this is no longer default behaviour; it can also be configured to store and will by default on the original version of Windows XP and lower Lan Manager hashes of the local user account passphrases, which can be attacked and broken easily.

It also stores local user account passphrases as NTLM hashes, which can be fairly easily attacked using " rainbow tables " if the passwords are weak Windows Vista and later versions don't allow weak passwords by default. To mitigate the threat of trivial brute-force attacks on local passphrases, older versions of Windows need to be configured using the Security Settings portion of Group Policy to never store LM hashes, and of course, to not enable Autologon which stores plaintext passphrases in the registry.

Further, using local user account passphrases over 14 characters long prevents Windows from storing an LM hash in the SAM - and has the added benefit of making brute-force attacks against the NTLM hash harder. Of course, if you consider the fact that EFS uses Triple DES or AES to encrypt files, you should use proper passphrases over 20 characters long to achieve equivalent strength against brute-force attacks.

When encrypting files with EFS - when converting plaintext files to encrypted files - the plaintext files are not wiped, but simply deleted. This means that they can be easily recovered unless they are overwritten. To fully mitigate known, non-challenging technical attacks against EFS, you should configure encryption at the folder level so that all temporary files like Word document backups which are created in these directories are also encrypted.

When you wish to encrypt individual files, copy them to an encrypted folder or encrypt the file "in place", and then securely wipe the disk volume. Anyone that can gain Administrators access can overwrite, override or change the Data Recovery Agent configuration. This is a very serious issue, since an attacker can for example hack the Administrator account using third-party tools , set whatever DRA certificate they want as the Data Recovery Agent and wait.

This is sometimes referred to as a two-stage attack, which is a significantly different scenario than the risk due to a lost or stolen PC, but which highlights the risk due to malicious insiders. When the user encrypts files after the first stage of such an attack, the FEKs are automatically encrypted with the designated DRA's public key. The attacker only needs to access the computer once more as Administrator to gain full access to all those subsequently EFS-encrypted files.

Even using Syskey mode 2 or 3 does not protect against this attack, because the attacker could back up the encrypted files offline, restore them elsewhere and use the DRA's private key to decrypt the files.

Of course, if such a malicious insider can gain physical access to the computer, you might consider all security features to be irrelevant, because he could also install rootkits , software or even hardware keyloggers etc. Files encrypted with EFS can only be decrypted by using the RSA private key s matching the previously-used public key s. The stored copy of the user's private key is ultimately protected by the user's logon password.

Accessing encrypted files from outside Windows with other operating systems Linux , for example is not possible — not least of which because there is currently no third party EFS component driver.

Further, using special tools to reset the user's login password will render it impossible to decrypt the user's private key and thus useless for gaining access to the user's encrypted files. The significance of this is occasionally lost on users, resulting in data loss if a user forgets his or her password, or fails to back up the encryption key. This led to coining of the term "delayed recycle bin", to describe the seeming inevitability of data loss if an inexperienced user encrypts his or her files.

Windows EFS supports a range of symmetric encryption algorithms, depending on the version of Windows in use when the files are encrypted:. Microsoft Wiki Explore.

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