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From: Per Jessen on 29 Aug 2010 14:46
Jim Lucas wrote:

> Per Jessen wrote:
>> tedd wrote:
>>=20
>>> Hi gangl:
>>>
>>> I realize that the problem stated herein has been solved by others,=

>>> so I'm not claiming I've done anything new -- it's only new to me.
>>> It was a learning experience for *me* and my solution may help
>>> others.
>>>
>>> In any event, I've finished creating a method for establishing what=

>>> I think is secure communication between two servers.
>>=20
>> First thought - you're reinventing the wheel. When I connect to a
>> server via https, I have secure communication.
>>=20
>=20
> First, it isn't the connection that he is trying to secure. He admit=
s
> to using HTTPS in his connections already.=20

I didn't bother reading far enough I guess.

> What I think he is trying to prevent (correct me if I'm wrong) is
> access to the data on the opposite server. He wants to make sure tha=
t
> the access to this data is only able to be done by the remote server.=
=20

If that is the objective, it's perhaps best solved by using TLS with a
client certificate/key. Well, that's what I would do.=20


--=20
Per Jessen, Z=C3=BCrich (15.6=C2=B0C)

From: Per Jessen on 29 Aug 2010 14:51
tedd wrote:

> Like in this example, I use HTTPS in all the steps yet one responder
> said "use HTTPS". That means: 1) He didn't understand what I was
> saying; 2) He didn't read what I wrote, which probably the reason for=

> #1.

You said "secure communication", which (in this context) is quite
clearly HTTP + TLS. I didn't bother reading the rest because I had
already had trouble understanding your previous questions.

> Also, as per another responders statement, using a SSL does not
> necessarily mean that the server is more secure.=20

Yes, it has no bearing on the security of the server, but using TLS
means the communication is. If you then also use client-side
certificates, you're really quite safe.


--=20
Per Jessen, Z=C3=BCrich (15.4=C2=B0C)

From: tedd on 29 Aug 2010 17:18
To all:

Part of the problem in discussing security is that there are all
sorts of security issues.

There is the obvious cleaning and scrubbing of data coming into your
site from outside sources such as from POST, GET, COOKIES, and such.

There's the security problem of communication between your users and
your server, thus HTTPS and SSL's come into play.

There is the security problem in what access your users have to your
data, such as in setting directory permissions, placing files
out-of-the-root, placing data in a database and controlling users
access to such data.

And then there is the security involved in what happens *if* your
server is hacked and all your "private" data is seen by a third
party. What does all that entail -- and -- how you might be able
protect yourself should be paramount in every developer's mind.

Now, I'm not a server guy, nor do I know what happens when a server
is hacked, nor do I know what data might be exposed. I will say it
would be nice to have a server guru, like Daniel Brown, wade in on
this and tell us what is the range of things that can actually happen
and what data might be exposed and how we might protect ourselves.

At this point, I don't know the answers to those questions, but in my
readings I found that if a server is hacked, then all data contained
on the site can be read by a third party. Even encrypted data can be
decrypted *if* the keys are exposed. In addition, access to the
database can happen if the user-name and password are kept in a file,
or code, that is exposed to the hacker after hacking. Everything is
exposed.

As such, that was my recent concern and my subsequent "Secure
Communication?" post -- it was a way to protect data.

Now, how likely is it that a server might be hacked -- again, I don't
know. However, I sent numerous emails corresponding with GoDaddy.com
as to what they would do *if* their servers were hacked and their
customer's sensitive data was exposed to a third party, which caused
their customers harm.

I assumed that GoDaddy.com had insurance policies and procedures in
place to mitigate damages for their customers, but unfortunately they
responded that each case would be handled on a "We'll see" basis --
and I think we all know what that means.

So, if you want to secure your data on a server, it means that you
should take steps to do that and not rely upon the host to do that
for you. Like I said, it would be nice to have a server guru wade in
on this to clarify things.

Cheers,

tedd

--
-------
http://sperling.com/
From: Per Jessen on 30 Aug 2010 02:28
tedd wrote:

> And then there is the security involved in what happens *if* your
> server is hacked and all your "private" data is seen by a third
> party. What does all that entail -- and -- how you might be able
> protect yourself should be paramount in every developer's mind.

IMHO, not in a normal context. A developer needs to be able to trust
that the server is as secure as the organisation expects.=20

> In addition, access to the database can happen if the user-name and
> password are kept in a file, or code, that is exposed to the hacker
> after hacking. Everything is exposed.

If somebody gains unauthorized access to your system, assume the worst.=


> Now, how likely is it that a server might be hacked -- again, I don't=

> know.=20

If it's not secured, 100%.=20

> So, if you want to secure your data on a server, it means that you
> should take steps to do that and not rely upon the host to do that
> for you. Like I said, it would be nice to have a server guru wade in=20=

> on this to clarify things.

There isn't really a lot to clarify. To reduce the risk of a server
being compromised:

impose physical access controls.=20
limit the open services, and run a firewall.=20
make sure your open services are secure (latest patches etc).=20

To reduce the impact should it get compromised anyway:

run your server in a DMZ.
run SElinux or AppArmor for access control.=20
do not store important passwords on the server.


If all of that isn't really within your reach because you don't have
your own server - get your own server and secure it. A leased server
is available for e.g. EUR50/month and that money is better spent than
you spending hour after hour trying to secure your application to run
on an insecure server.=20


--=20
Per Jessen, Z=C3=BCrich (10.4=C2=B0C)

From: Paul M Foster on 30 Aug 2010 15:58
On Sun, Aug 29, 2010 at 12:24:31PM -0400, tedd wrote:

> Hi gangl:
>
> I realize that the problem stated herein has been solved by others,
> so I'm not claiming I've done anything new -- it's only new to me. It
> was a learning experience for *me* and my solution may help others.
>
> In any event, I've finished creating a method for establishing what I
> think is secure communication between two servers. I've written two
> scripts that run on different servers, which confirm communication
> between them via hard-wired urls and creating/writing/reading a
> url-confirmation file.
>
> The purpose of this exercise was to simply to keep database-access
> data (i.e., user_name, password, key to decryption) secret. However,
> the secret could be anything you want to keep secret -- secret being
> defined as no data residing on the server of concern while allowing
> that server access to the data when needed and under authorization.
>
> Here's what I've done -- I have two domains, namely webbytedd.com
> (the Master) and php1.net (the Slave) -- both domains reside on
> different servers. The domain names really don't matter, it's just
> that this method currently works between those two domains.
>
> Statement of Requirements:
>
> 1. The Master requires "access" to it's database.
>
> 2. The Slave keeps "access" to Master's database in it's own database.
>
> 3. It's required that "access" remain secret in the event that the
> Master is hacked.
>
> *The term "access" above is defined as database-access data, such as
> user_name, password, and key to decryption.
>
> Description of Method:
>
> 1. When the Master wants access to it's database, it first creates a
> url-confirmation file and writes a token to that file, which resides
> on the Master. I've used time() as the token, but the token could be
> any variable -- it really doesn't make much difference other than the
> value should be different each time.
>
> 2. The Master then sends a cURL request to the Slave via a POST where
> the POST variable contains the token.
>
> 3. The Slave when receiving the POST request from Master reads the
> token from the newly created url-confirmation file residing on the
> Master and then compares that token with the token provided by the
> POST -- if the tokens match, then the Slave returns "the access" to
> the Master. If not, the process fails.
>
> 4. After receiving "access" the Master deletes the url-confirmation
> file and continues with it operation. If the Master does not receive
> "access" then it deletes the url-confirmation file and exits.
>
> This method sounds simple enough and does several things.
>
> 1. There is no "access" stored on the Master.
>
> 2. While the Slave has "access" for the Master stored in its
> database, the access to the Slave's database is kept in an
> out-of-root (not open to the web) file. Note, in this case, this was
> not possible on the Master because the host did not allow out-of-root
> files -- but that is only tangential to the problem addressed here.
>
> 3. If a hacker did obtain access to the Slave database, then the
> hacker would discover the contents have been encrypted and only the
> Master has the decryption key kept in it's database.
>
> 4. If a hacker did obtain access to the code residing on the Master,
> then the hacker could not access the Master's database because the
> "access" data is recorded on another server (i.e., Slave).
> Furthermore, the hacker could not get the code to run anywhere else
> because the Slave's "look-up URL" for the url-confirmation file is
> hardwired to the Master address.
>
> 5. And lastly, all communication between both domains is done via https.
>
> Now, for the exception of both server's being hacked at the same
> time, what could go wrong?
>
> Cheers,
>
> tedd

A couple of things I'm unsure about. Here's what I *think* is going on:

The actual database with the Master's data is located on the Master
machine.

The "keys" to this data are contained on the Slave server, in *its*
database.

The Slave's database is encrypted, so that the "keys" to the Master
database can't be derived even if a hacker hacks the "Slave" machine.

The "keys" to the Slave database are held by the Master.

So when the Master asks the Slave for access, it must send across the
keys for the Slave to access its own database. The Slave then decodes
its database and sends the Master back the "keys" for the Master's
database. The Master can then make queries to its database unfettered.

Is that about right?

Other than the fact that this solution should be rife with latency
issues, it seems like it would be secure.

I assume you're doing this as an academic exercise. If you had an actual
client who wanted to go to this much trouble to secure their data, I
think I would opt for the previously suggested solution of getting a
dedicated server or two.

Paul

--
Paul M. Foster
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