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Re: Was Re: RAID 5 drive replacement schedule - Now "Availability"
From: Adriel Desautels <adriel () netragard com>
Date: Mon, 23 Jun 2008 08:51:36 -0400

Mike,
Its really quite simple and I've already given you examples, which you seem to have ignored. The importance of Availability depends on the entity and the subject. In some cases the entity may not consider a lack of availability to be a security issue as much as they do an IT issue. Sometimes they don't even consider it to be an issue at all.

With respect to what you wrote, don't put words into my mouth. I never said that an email server outage wasn't a critical problem or a security issue. I also never said that a DDoS wasn't a security issue. By definition those two things can "bring harm" and as such become a security issue.

I am saying that Availability is only a security issue in certain (possibly most but not all) cases. If the lack of Availability brings harm then it becomes a security issue. That said, it does not always bring harm and as such isn't always a security issue. In those non-harmful cases the issue falls under the responsibility of IT/Networking/Whatever you want to call it. If it brings harm or not entirely depends on the entity.
        
If a business has an FTP server that they use once a week on a Wed at 1:00:PM EST for 15 minutes every Wed to perform non-critical, non-sensitive data transfers, what is the security implication of it going down on a Thursday at 8:00:AM EST?

The definitions that I provided are accurate. The word security wasn't created by the IT Security industry, nor was the word availability. That said, your wikipedia definition of Information Security was spot on, but I only asked for you to define "security".

        Is the horse dead yet?

        

Regards,
        Adriel T. Desautels
        Chief Technology Officer
        Netragard, LLC.
        Office : 617-934-0269
        Mobile : 617-633-3821
        http://www.linkedin.com/pub/1/118/a45

        Join the Netragard, LLC. Linked In Group:
        http://www.linkedin.com/e/gis/48683/0B98E1705142

---------------------------------------------------------------
Netragard, LLC - http://www.netragard.com  -  "We make IT Safe"
Penetration Testing, Vulnerability Assessments, Website Security

Netragard Whitepaper Downloads:
-------------------------------
Choosing the right provider : http://tinyurl.com/2ahk3j
Three Things you must know  : http://tinyurl.com/26pjsn


Mike Hale wrote:
"Your definition of Availability is not correct."
Correct.  I used a fairly specific definition in a security context,
not one I grabbed from Dictionary.com.  Sorry.

"The term Availability has nothing to do with authorization."
Fine.

"Security can, but does not always have something to do with
Availability and Visa Versa"
When you're talking about information security, yes it does.

"That entirely depends on the entity."
Wrong if you're talking about InfoSec.

"Availability is a vague term that is not always a component of security"
It's an integral component of an effective InfoSec policy.  It's up to
the user to define it, specifically, for the network he or she is
securing.

"As such your CIA acronym..."
It's not 'my' acronym.  It's one the core components of the SANS
Security 401, as well as many other basic security classes out there.

So are you saying that, say, an email server outage is not a
'critical' situation for a large company?  Is a DDOS attack on a
company that brings down it's network not a critical issue?  Is the
Janitor accidentally kicking out the plug for the core switches not
critical?

All that falls under the availability heading, and can not be ignored
nor marginalized.

"Anyway, I think that we've beaten this subject to death."
Not at all.  I, for one, would love to see how you justify ignoring
the availability of data and resources in a company's network.

On 6/21/08, Adriel Desautels <adriel () netragard com> wrote:
Mike,
       First, Thank you very much. Your definition of Availability is not
correct. The word Availability is an adjective that means "suitable or ready
for use; of use or service; at hand". When one speaks of the Availability of
data, systems, etc, they are talking about the use of a service or the
readiness of the service for use. The term Availability has nothing to do
with authorization.

       Likewise, your definition of Security is not correct. The actual
definition of security is "freedom from danger, risk, etc.; safety."
Security can, but does not always have something to do with Availability and
Visa Versa. That entirely depends on the entity.

       The reason why I am spending so much of my time discussing this is
because our industry has a serious problem with defining terms and using
terms properly. Availability is a vague term that is not always a component
of security, but it can be. It all depends on what "being secure" means to a
particular entity. The same risks to different entities do not always carry
the same weight. As such your CIA acronym does not always hold true.
Security is not the product of CIA, it can't be defines by such basic terms.
Security is an ongoing process made up of many sub-processes.

       Large financial corporations consider the loss of availability of
transaction systems to be critical as it creates significant harm to their
business. In this case I agree that Availability is a security concern.
Security is freedom from danger, harm can be the result of exposure to
danger.

       Likewise, the same Large financial corporations consider the outage
of their FTPS servers to be non-critical because there may be no harm caused
to their businesses as the result of an outage. No harm, no foul, no
security concern. (Remember, we're not talking about a compromise, just an
outage that results in the lack of Availability.)

       With all that said the creation of a drive replacement schedule is
not a security concern. Creating that schedule does not introduce risk. The
execution of that schedule, the replacement of those drives, and the
disposal of those drives can introduce risk. Those risks are security
concerns for "some" entities.

       Anyway, I think that we've beaten this subject to death.


Regards,
       Adriel T. Desautels
       Chief Technology Officer
       Netragard, LLC.
       Office : 617-934-0269
       Mobile : 617-633-3821
       http://www.linkedin.com/pub/1/118/a45

       Join the Netragard, LLC. Linked In Group:
       http://www.linkedin.com/e/gis/48683/0B98E1705142

---------------------------------------------------------------
Netragard, LLC - http://www.netragard.com  -  "We make IT Safe"
Penetration Testing, Vulnerability Assessments, Website Security

Netragard Whitepaper Downloads:
-------------------------------
Choosing the right provider : http://tinyurl.com/2ahk3j
Three Things you must know  : http://tinyurl.com/26pjsn


Mike Hale wrote:
Availability is allowing your authorized users to access the data when
they need to.

"that in its self is not _always_ a security concern, but it can be."
I disagree with you.  Availability is a fundamental portion of it
because without availability, that data is useless.  If you don't have
access to it when you need it, I think your security system has
failed.

You're also correct that if a system crashes, data is no longer
available.  Sometimes, attacks on a network seek to do just that.

As far as the definition of security (especially in terms of data),
papers have been written trying to pin it down.  I think at it's most
basic, however, is CIA.  Confidentiality, Integrity and Availability.

It's about preventing unauthorized access and change while maintaining
it's useability to authorized users.

On 6/20/08, Adriel Desautels <adriel () netragard com> wrote:

Mike,
      Thanks for responding so quickly, this is an interesting argument.

When you talked about availability, you did not say "data availability".
Even with "data availability" being the subject, that in its self is not
_always_ a security concern, but it can be.

Can you provide me with your definition of Availability with respect to
Security?


Availability is not vague, nor "can" it have a role in security.  It's
in integral part, along with Confidentiality and Integrity.  If it's
ignored, the system itself has already failed, and is simply waiting
for someone to come along and take advantage of it.

If a system crashes it is not available, its data is not available, and
it
can not be taken advantage of. If the data can't be accessed then isn't
it
more secure than it was when it was available?

Can you also provide me with your definition of security?





Regards,
      Adriel T. Desautels
      Chief Technology Officer
      Netragard, LLC.
      Office : 617-934-0269
      Mobile : 617-633-3821
      http://www.linkedin.com/pub/1/118/a45

      Join the Netragard, LLC. Linked In Group:
      http://www.linkedin.com/e/gis/48683/0B98E1705142


---------------------------------------------------------------
Netragard, LLC - http://www.netragard.com  -  "We make IT Safe"
Penetration Testing, Vulnerability Assessments, Website Security

Netragard Whitepaper Downloads:
-------------------------------
Choosing the right provider : http://tinyurl.com/2ahk3j
Three Things you must know  : http://tinyurl.com/26pjsn


Mike Hale wrote:

"That is not a security issue though. That is an IT related issue"
You're correct on that one, and I have no disagreement.

Going back to CIA and the pyramid...

"so on don't hold much water in my opinion."
So you're saying that data availability is marketing speak and not
something that needs to be built into a security system?
Seriously?

"What does creating a drive replacement schedule have to do with
security"
That's not what i was addressing.  I was addressing your statement
that "Availability is a vague term that can, but does not always have
a role in security."
Availability is not vague, nor "can" it have a role in security.  It's
in integral part, along with Confidentiality and Integrity.  If it's
ignored, the system itself has already failed, and is simply waiting
for someone to come along and take advantage of it.

On 6/20/08, Adriel Desautels <adriel () netragard com> wrote:


Mike,
     First off, there are multiple "security pyramids", each of them
different, most of them created for marketing, sales, etc. So CYA,

TESSM,

and so on don't hold much water in my opinion.

     With that aside, I'm open to being educated but I still
disagree
that

creating a drive replacement schedule requires any security
expertise.
As

such I do not see the subject as being a security topic. There are

certainly

aspects of security that can be impacted by the act of changing the

drives,

I won't argue that. So...

What does creating a drive replacement schedule have to do with

security?

Educate me.


Regards,
     Adriel T. Desautels
     Chief Technology Officer
     Netragard, LLC.
     Office : 617-934-0269
     Mobile : 617-633-3821
     http://www.linkedin.com/pub/1/118/a45

     Join the Netragard, LLC. Linked In Group:

http://www.linkedin.com/e/gis/48683/0B98E1705142


---------------------------------------------------------------
Netragard, LLC - http://www.netragard.com  -  "We make IT Safe"
Penetration Testing, Vulnerability Assessments, Website Security

Netragard Whitepaper Downloads:
-------------------------------
Choosing the right provider : http://tinyurl.com/2ahk3j
Three Things you must know  : http://tinyurl.com/26pjsn


Mike Hale wrote:


Philippe is actually correct.

CIA forms the security pyramid.

Confidentiality.
Integrity.
Availability.

That's the three components of data in a secure system.  Most
companies can only afford to focus on one of those aspects, but if
you
ignore the others, you don't have a secure system.

On 6/20/08, Adriel Desautels <adriel () netragard com> wrote:



Philippe,
    I disagree with you and I think that the definition of
security

that


you provided is partial, but thats just my opinion. Availability
is
a

vague


term that can, but does not always have a role in security.

Determining

what


the proper schedule is for a drive replacement policy is
something
that

can


be done by IT without the security team. Deciding how to dispose
of
the

drives on the other hand is security.


Regards,
    Adriel T. Desautels
    Chief Technology Officer
    Netragard, LLC.
    Office : 617-934-0269
    Mobile : 617-633-3821
     http://www.linkedin.com/pub/1/118/a45

    Join the Netragard, LLC. Linked In Group:


http://www.linkedin.com/e/gis/48683/0B98E1705142



---------------------------------------------------------------
Netragard, LLC - http://www.netragard.com  -  "We make IT Safe"
Penetration Testing, Vulnerability Assessments, Website Security

Netragard Whitepaper Downloads:
-------------------------------
Choosing the right provider : http://tinyurl.com/2ahk3j
Three Things you must know  : http://tinyurl.com/26pjsn


Rivest, Philippe wrote:



Adriel & Murda

It is a security issue the way you store your data. In regards
to
the

raid


technologies, raid 5 improves the availability of the data by

making

sure


that a single drive failed will not impact the availability of
the

data.


Remember that security is 1- Confidentiality
2- Availability
3- Integrity

The main goal of a Raid 5 is to help #2. You are referring to
the

disposal


of



the HD which is the issue of confidentiality and that is not
what

Murda


was



aiming at. If it is, go for encryption, degaussing,
destruction
and

just


plain format (if the data is not confidential).

As I explained to him offline, the MTTF and MTBF is about the
same
for

2


HD



bought/constructed at about the same time. How ever, those are
not


absolute



numbers that state that, if one drive fails the other one is
about
to

go


too.



It's more an estimated value against which you should have
some
confidence/hope, your drive should not fail before X hours (it

could

go


before but the average is X).

In a raid 5, Drive A, B and C are online and working (they are
the

same


drive



bought at the same time). Drive A fails, you should NOT change

drive B

& C


unless they are failing also. If you do, the cost of your raid
5
will

be


greater then what it should be (the replacing of the parts are

going

to


cost



a lot). Change drive A and hope drives B & C will last longer.


The only issue is that 2 drives fail at the same time, which
is
very

improbable. And if it does, you should be going for your back
ups.

I do hope this clarified the questions and that I wasn't to

unclear

with


my



details!

Merci / Thanks
Philippe Rivest, CEH
Vérificateur interne en sécurité de l'information
Courriel: Privest () transforce ca
Téléphone: (514) 331-4417
www.transforce.ca


-----Message d'origine-----
De : listbounce () securityfocus com


[mailto:listbounce () securityfocus com] De


la



part de Adriel Desautels
Envoyé : 20 juin 2008 11:27
À : Murda Mcloud
Cc : security-basics () securityfocus com
Objet : Re: RAID 5 drive replacement schedule

Murda,
    The real answer to your question is that it is very, very



improbable that all of the drives in the array will fail at the
same

time.


Most drives are good for a certain period of years, after which

point

you


are getting "extra time".



    That is not a security issue though. That is an IT related


issue.


The



security issue comes into play when you dispose of your
drives. Do
you


shred them, just throw them in the dumpster, how do you dispose
of
them?


Regards,
    Adriel T. Desautels
    Chief Technology Officer
    Netragard, LLC.
    Office : 617-934-0269
    Mobile : 617-633-3821
    http://www.linkedin.com/pub/1/118/a45

    Join the Netragard, LLC. Linked In Group:



http://www.linkedin.com/e/gis/48683/0B98E1705142




---------------------------------------------------------------
Netragard, LLC - http://www.netragard.com  -  "We make IT
Safe"
Penetration Testing, Vulnerability Assessments, Website
Security
Netragard Whitepaper Downloads:
-------------------------------
Choosing the right provider : http://tinyurl.com/2ahk3j
Three Things you must know  : http://tinyurl.com/26pjsn


Murda Mcloud wrote:




In my mind, this a security related question as it has to do

with


ensuring



availability.

Does anyone have links towards any whitepapers etc that
suggest


replacement



of disks in a RAID 5 array as part of a maintenance cycle?

If all the drives in an array are the same age and one
fails;
does

this



mean




the others are more likely to fail. I'd imagine so as they
have
had

the



same




amount of usage.






















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