Hmmmm here is a post I took from the bugtraq group on Google about
Linkpoint.
NOTE: I AM NOT THE ONE THAT DID THIS INVESTIGATION. I just find it
interesting.
== Some Background ==
LinkPoint is the name of the API that Card Service International
(one of the biggest online merchant account providers) uses for
communication between a merchant's servers and their credit-card
gateway.
The LinkPoint client API communicates with the credit-card gateway
using an SSL-based protocol. Authentication and encryption is
facilitated with x509 digital certificates (the same ones that https
uses).
You must provide the client with two pieces of information for it to
authenticate to the gateway server. The first is what CSI calls
"Store Name" -- it's actually a six digit number. The second is the
path to the certificate file they send you.
== The Problem ==
Although I have not discovered a technical (code) security problem,
I
believe there is a serious procedural security problem in they way
CSI initially sets up accounts.
When you are approved for a CSI merchant account (or even when you
are approved for a test account), CSI sends you two emails. One of
the emails has the subject "Welcome to LinkPoint API" (the other is
unimportant). This email contains two pieces of information:
The gateway server's hostname
Your "Store Name" (the six digit number)
Plus, they attach your certificate AND _private key_ to the bottom
of
the message. The idea is that you copy and paste the cert + private
key into a file for the client API to use when it connects.
I don't think I need to spell out the problem any further for
everyone
on this list. Basically, they are sending all of the information
you
need authenticate as a merchant through plain, unencrypted, email.
You would need a few more things to exploit this potential security
hole. Namely, you would need the CSI API and some knowledge of how
to use it. This appears to be an attempt at security through
obscurity.
Also, you would obviously need a way to get the plain email
(sniffing, etc)
Notes: * The digital certificates do not have a passphrase.
* The LinkPoint API documentation is publicly available at:
http://www.cardservice.com/inetserv/lpapi.pdf
== Card Service's Response ==
My attempt to contact CSI lead to a phone call from the
"Lead Senior Tech" in the "API Support" department of CSI.
Since I did not type this email while I was on the phone, all of the
quoted comments bellow are from memory and probably aren't exact.
They are, however, pretty close to what was said.
I spoke with this person for about ten minutes and was not satisfied
with his response. This person's basic theme was "It's never
happened
before and there are security precautions on the back-end".
I explained to him that using the information in their email, I
could
pose as the merchant -- and after a while, he reluctantly agreed. I
then asked him to clarify how that isn't a serious security problem,
and he quickly responded with something along the lines of "lets say
you can pose as the merchant, what are you going to do?". I
responded
by saying "I'd start posting refunds to my card" and he said "the
refund option has to be enabled per merchant". Next, I told him I
could charge cards. His response to this was that "well, then you
would
be giving money to the merchant".
I suggested to him that if I was a malicious user, I could charge
random cards with random amounts to the merchant's account. His
response: "our backend would detect that". I asked for
clarification
and realized that the security he is talking about is their "Fraud
Protection" system. From my knowledge (and I've used the CSI API in
several projects) and according the the API documentation available
online, this system just blocks an end-user from attempting to
charge
credit cards if they've had repeated failures. The key here is that
it uses the _end user's_ (the person submitting a credit card to the
merchants site -- the web browser) IP. This IP is sent to the
gateway
server from the client API. It's very simple to write a program
which
charges a whole bunch of cards and makes the API think each one came
from a different IP (especially since the IP is just one of the
items
in the struct you pass to the client API). Obviously, the Fraud
Protection provided by the gateway server is not meant to prevent a
fraudulent merchant -- it is made to prevent fraudulent customers
from
fooling legitimate merchants. In this scenario, you _would be_ the
merchant and therefore not subject to fraud checks.
At this point, I had given up. I have a hard time understanding how
it's "not a security problem" for me to be able to pose as the
merchant. Even if I can't refund my card, I can cause a lot of
unwanted trouble by charging cards, etc.
== Summary ==
Unprotected Digital Certificates (no passphrase) that establish the
identity of a merchant are sent via unencrypted email, along with
the
merchants "Store Name". Someone with access to the LinkPoint API
could
use this information to pose as the merchant and have access to all
of
the same functions and information as the merchant (charge a card,
etc).
-chris.alvarado
[ application developer ]
4 Guys Interactive, Inc.
http://www.4guys.com
"We create websites that make you a hero."
-----Original Message-----
From: Lee Fuller [mailto:[EMAIL PROTECTED]]
Sent: Friday, November 22, 2002 2:25 PM
To: CF-Talk
Subject: RE: Payment Gateways? (Was: OPINIONS: PayFlow Pro and CF
Integration?)
Thanks for the info Jason.
I've looked at Authorize.Net again. Have had it integrated as part of
our storefront software for some time. However, I've not dealt with
them directly. The user experience is a big thing for me. So I'm
wanting to make certain that the end-user's ability to manage their
account/charges/voids, etc., is powerful and easy.
How would you rate Authorize.net on these issues?
Lee
PS - I thought about moving this discussion.. But it seems relevant to
all of us here. Mike will tell us otherwise, I'm sure, if I'm wrong. ;)
| -----Original Message-----
| From: Jason Miller [mailto:[EMAIL PROTECTED]]
| Sent: Friday, November 22, 2002 3:19 PM
| To: CF-Talk
| Subject: Re: Payment Gateways? (Was: OPINIONS: PayFlow Pro
| and CF Integration?)
|
|
| Is LinkPoint by Card Service International? I see their
| little logo on
| the page when I found linkPoint If so - don't let their promise of
| service and talk of them being one of the largest sway you.
|
| I have a list of clients that are incredibly unhappy. Although fairly
| simple- roadblocks left and right. Customer Service departments are
| horrendous. And to top it off - being a business man - reseller fees
| happen to be a plus - Well they managed to scam me out of
| about $1800 in
| client referrals.
|
| So - horrible service, what I think as a non impressive
| product. beware.
|
| Also - I had my own companies card processing go through them. They
| conveintly had me lease the software - for $3500 for 3 years.. then
| proceed to tell me that fairmarket was $2800 on the software
| for buyout
| - or I had to pay a cancellation fee - of about $400 - all
| very gray in
| the contracts.
|
| I tried to convert a Link Point account to an upgraded version - and
| after 6 months of trying to get my account changed - I
| finally gave up.
| I mean - I was trying to UPGRADE ....
|
| On trying to cancel the service - they also were kind enough not
| releasing my account for an additional 6 months - because I
| did not send
| the proper formated letter - When resolving it -they so happened to
| delay it for enough weeks - where I missed this ridicoulous
| cancellation
| date ( one of those- on the 3rd monday of the 16 month of this year
| prior to notifying us by this date" type date")
|
| All in all - 2 years of bad service! *grin
|
| I have used authorize.net on 4 clients - affordable -
| coldfusion really
| easy to integrate with. Worth checking out.
| Good Luck,
| jay miller
|
| Lee Fuller wrote:
|
| >Yeah.. I've noticed that it's fairly simple.
| >
| >Unfortunately, it tends to be expensive for the little guys
| out there
| >-- which we seem to be running into a lot, these days. I've
| looked at
| >SimplePay, and LinkPoint. They're much cheaper. But
| question is.. Are
| >they as reliable and workable?
| >
| >Anyone have experience with these or others that they would like to
| >share?
| >
| >| -----Original Message-----
| >| From: Frank Mamone [mailto:[EMAIL PROTECTED]]
| >| Sent: Friday, November 22, 2002 11:38 AM
| >| To: CF-Talk
| >| Subject: Re: OPINIONS: PayFlow Pro and CF Integration?
| >|
| >|
| >| Excellent product. Easy to use and setup.
| >|
| >|
| >| ----- Original Message -----
| >| From: "Lee Fuller" <[EMAIL PROTECTED]>
| >| To: "CF-Talk" <[EMAIL PROTECTED]>
| >| Sent: Friday, November 22, 2002 11:14 AM
| >| Subject: OPINIONS: PayFlow Pro and CF Integration?
| >|
| >|
| >| > Quick thoughts, pitfalls, opinions?
| >| >
| >| > TTAIA
| >| >
| >| >
| >| >
| >|
| >
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
Archives: http://www.houseoffusion.com/cf_lists/index.cfm?forumid=4
Subscription:
http://www.houseoffusion.com/cf_lists/index.cfm?method=subscribe&forumid=4
FAQ: http://www.thenetprofits.co.uk/coldfusion/faq
This list and all House of Fusion resources hosted by CFHosting.com. The place for
dependable ColdFusion Hosting.
