[cabfpub] SHA-1 exception request

Gervase Markham gerv at mozilla.org
Mon Oct 10 16:02:05 UTC 2016

On 08/10/16 13:44, Dean Coclin wrote:
> “First Data has successfully updated all other internal systems,
> websites, networks and POS devices to SHA-256.  Where FD has control
> we are compliant.” However, the majority of POS devices are created,
> sold, deployed and maintained by third parties. Merchants are free to
> obtain POS devices from these providers and use them with FD's
> infrastructure.

But those POS devices won't work with FD's infrastructure unless they
contain the roots which anchor the certificates that FD uses. Given
that, does FD have a policy for which roots, algorithms etc. need to be
supported by terminals in order to guarantee continued operation?

I assume you don't agree to take the burden of supporting any old
device, however old or buggy or badly designed.

> Regarding the Root removal policy:  Many of the POS devices created
> by other parties are simply applications running on standard Windows
> or Linux distributions.  Those devices contain the same root stores
> that browsers trust.  Many of them are Java applications, which by
> default use the Java trust store that contains many of the same roots
> trusted by browsers.

Well, those don't sound too hard to update. I was assuming we were
talking about embedded devices with limited crypto processors. Dean
often uses the example of the embedded device taken out of the drawer
once a year for the bake sale.

So can we assume that devices in the "Windows/Linux/Java app" category
have not been updated either because the vendor has withheld the
knowledge of the necessity of this from the merchant, or the merchant
has ignored the warnings?

(I'm sure it can't be because the vendor has stopped supporting the
software, because unsupported POS software which handles payments would
be a massive security risk.)

> [First Data] As stated previously, the ecosystem is very large and
> complex. There are over 1,200 different POS applications/devices
> running various versions of operating systems, patch levels, POS
> software revisions etc.,  which use the First Data infrastructure.

And is it right that First Data takes no responsibility for the level of
security of those clients (e.g. whether they are running updated and
secure OS versions)? That's the responsibility of the merchant and the
POS vendor?

Or do you have some requirements, e.g. PCI compliance?

> Most of these are managed by third party providers, outside of First
> Data control.
> Given the complexity of device ownership it would be impossible to
> survey all devices and the list of roots that they trust.

So what was your plan if the one root you know they all trusted (because
it's the one you were using) got compromised and ceased issuing

> If you are one end of a secure connection and you can't communicate
> security-related information to the person controlling the other end,
> even when given 12 months to do it, you are doing it wrong.
> [First Data]  As explained, FD doesn't have a direct business
> relationship with many of the merchants. The communication and
> administration of POS devices are handled by the POS vendors who sold
> the merchants their POS system.

So presumably when this system stops working, the merchant will go back
to the POS vendor and say "Hey, you knew this was coming because First
Data told you - why didn't you warn me?" And either they will reply "We
did, and you ignored it - look here", or they will reply "Oops", at
which point the merchant gets a new POS vendor.

> The POS provider is required maintain PCI compliance of their device.

And PCI compliance doesn't yet require use of SHA-256? What is the exact
status there, with deadlines?

> [First Data]  Based upon demands from our Distribution Systems, we
> will be starting this exercise on Tuesday October 18th.

9 days before your certificates expire?

To be honest, the trouble with your request is moral hazard. Various
companies have put in massive amounts of effort to deal with this
deadline - or, at least, had the foresight to stockpile certificates so
they had until December 31st. If we continue to grant extensions, we
penalise those companies which have put in the effort and favour those
who have not. Does First Data really have a more eclectic and
complicated mix of clients, and a longer communications distance between
you and the merchants, than other payment processors?

Do any of the other root store operators have thoughts on this matter?


More information about the Public mailing list