RE: Protecting sensitive files on a Windows file server

["Roger A. Grimes" <roger () banneretcs com>]

In EFS, it takes me 5 minutes to remove the recovery key from the
administrators and choose a new, more secured recovery agent. 

But your last sentence says it all.

-----Original Message-----
From: Tyler, Grayling [mailto:ggtyler () foodlion com] 
Sent: Wednesday, June 21, 2006 4:24 PM
To: Roger A. Grimes; paul.johnson8 () gmail com; security basics
Subject: RE: Protecting sensitive files on a Windows file server

And you absolutely correct. The point I failed to get across was that if
the intent was to protect the files from the administrators that the
recovery key could be problematic. Not to mention the other areas you
just mentioned (e.g. devices with non-NTFS files systems).   

As always, protecting information has to be balanced with the need to
use it for business processes. So unless the data is so sensitive that
it warrants taking extreme measures (Two factor access and encryption
with the token stored in a dual combo safe requiring two separate
individuals to open etc...) or is mandated by security compliance
requirements, then security configuration and monitoring of the storage
location normally suffices.

With that said, its always situational-dependent so your mileage may
vary (smile).


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resolution to your calls.

-----Original Message-----
From: Roger A. Grimes [mailto:roger () banneretcs com]
Sent: Wednesday, June 21, 2006 3:28 PM
To: Tyler, Grayling; paul.johnson8 () gmail com; security basics
Subject: RE: Protecting sensitive files on a Windows file server

Grayling,

I thoroughly disagree with you about the recovery key issue. Recovery
keys aren't a problem. You have to have backup keys in case the original
keys are lost. No one should implement any encryption strategy without
first deploying a reliable key archival\recovery solution. 

It takes an admin password or to be logged in as the normal user to
recover EFS-protected files. If I can do either of those two things, I
don't care what your encryption program is, it's game over. I can just
retrieve your keys, install a keylogging trojan to capture your
passphrase protecting your keys, or just grab the files when the
original user views them.

The problem isn't key recovery, it's other operational issues. For
instance, EFS only works on NTFS partitions. That's a major problem for
an enterprise-wide encryption platform, which is trying to protect data
on non-NTFS media (e.g. USB keys, cd-roms, dvd's, etc.)

Roger

-----Original Message-----
From: Tyler, Grayling [mailto:ggtyler () foodlion com]
Sent: Wednesday, June 21, 2006 2:49 PM
To: Roger A. Grimes; paul.johnson8 () gmail com; security basics
Subject: RE: Protecting sensitive files on a Windows file server

I agree that using the password protection from within outlook isn't
especially secure (using the file encryption is better though). EFS
aren't much better because of the recovery keys.  If all you're doing is
keeping the honest people honest then either would likely suffice. 

If its honest-to-goodness sensitive material that you want to protect
from not so honest people then use the RSA with token or PGP.



All communication regarding everyday IT support needs such as IT
problems / incidents should be directed to the ITCRC team at x2848
instead of contacting the various associates directly within the IT
department. 
By logging all problems / incidents with the ITCRC team, this will
provide us more visibility into the various types of calls we are
receiving, trending of these calls, numbers of calls, etc. The ITCRC
team will bring more attention to your issues and allow prompt
resolution to your calls.

-----Original Message-----
From: Roger A. Grimes [mailto:roger () banneretcs com]
Sent: Tuesday, June 20, 2006 9:01 PM
To: paul.johnson8 () gmail com; security basics
Subject: RE: Protecting sensitive files on a Windows file server

-See replies below. 

Roger

*****************************************************************
*Roger A. Grimes, InfoWorld, Security Columnist *CPA, CISSP, MCSE:
Security (2000/2003/MVP), CEH, yada...yada...
*email: roger_grimes () infoworld com or roger () banneretcs com *Author of
Professional Windows Desktop and Server Hardening (Wrox)
*http://www.amazon.com/gp/product/0764599909
*****************************************************************



-----Original Message-----
From: paul.johnson8 () gmail com [mailto:paul.johnson8 () gmail com]
Sent: Tuesday, June 20, 2006 7:54 PM
To: Roger A. Grimes; security basics
Subject: Re: Protecting sensitive files on a Windows file server

We discovered with Office 2003, using the default Office 97/2000
compatible encryption type to protect the files, it is possible to
recover the passwords/data using software such as Elcomsoft Password
recovery (which can also break EFS) and online password/data recovery
services no matter how long the password or complexity in under 5 mins.

-It's worse than that. Office passwords can always be removed (set to
blank) because the password is stored in a known and editable location.

-Elcomsoft does not "crack" EFS private keys. It breaks the
Administrator account password (or uses the logon Administrator
credentials) to programmatically gain access to the otherwise protected
EFS private key. If the intruder breaks your Admin password or is able
to get logged on as Administrator, it's always game over...and cracking
EFS keys is only one your problems.

How are others protecting this information in their place of work?

-Most aren't. Just read the papers. Of those that are, most are using
EFS (again most users aren't), PGP, RSA, or some other commercial
solutions. There are dozens of commercial encryption solutions, and
kudos to you for looking into this.


On 21/06/06, Roger A. Grimes <roger () banneretcs com> wrote:
> There are many great commercial solutions, like PGP Desktop, but EFS 
> is free and works well if you handle key archival seriously.
>
> EFS works well, but it is not as eloquent as many of the other 
> solutions (don't forget TrueCrypt for a free solution). For example, 
> EFS only encrypts data while its stored on the hard drive, but the 
> data is decrypted (using EFS alone) when copied across the network or 
> down to other media. PGP Desktop, with NetShare, allows the files and 
> keys to be managed easier and to remain encrypted where ever they
ended up (i.e.
> USB key, CD-ROM, etc.); and with a single encryption key.
>
> Office 2003 encryption isn't good encryption; easy to bypass.
> Winzip leaves unencrypted recoverable temp files.
>
> Just my one-half cent. I haven't tried the RSA solution.
>
> Roger
>
> *****************************************************************
> *Roger A. Grimes, InfoWorld, Security Columnist *CPA, CISSP, MCSE: 
> Security (2000/2003/MVP), CEH, yada...yada...
> *email: roger_grimes () infoworld com or roger () banneretcs com *Author of 
> Professional Windows Desktop and Server Hardening (Wrox)
> *http://www.amazon.com/gp/product/0764599909
> *****************************************************************
>
>
>
> -----Original Message-----
> From: paul.johnson8 () gmail com [mailto:paul.johnson8 () gmail com]
> Sent: Monday, June 19, 2006 7:39 PM
> To: security basics
> Subject: Protecting sensitive files on a Windows file server
>
> We are looking for a secure way to store very sensitive files on our 
> Windows servers.  The data is shared. We will turn on full auditing, 
> create hidden shares and a security group.
>
> Which type of protection would be most suitable:
>
> Office 2003 encryption
> Windows EFS
> Winzip 9.x encrypted archives
> RSA SecurID Windows Agent (2 factor authentication) PGP Desktop Pro
>
> Our concern with the Windows/Office encryption types is that it could 
> be cracked - ie. someone could get hold of the file and run some kind 
> of password recovery on the file and access the data.
>
> Any ideas on how to approach this would be much appreciated.
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