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Re: [Full-Disclosure] Clear text password exposure in Datakey's tokens and smartcards
From: "Kevin Sheldrake" <kev () electriccat co uk>
Date: Fri, 06 Aug 2004 12:25:04 +0100
I don't doubt the widespread inherent nature of this vulnerability.
Smart cards used with PCs as the man-machine-interface is simply asking
for trouble IMHO. Unless I'm mistaken, there is very little that can be
done about this without redesigning/replacing current smart cards.
Obviously, bespoke MMIs (such as door access systems) are less vulnerable
to this issue. My problem is that people seem to view smart cards as a
panacea, as a place to store digital certificates or 'identities' and then
use them to 'prove' who they are.
Don't even start me on biometrics; if there is a PC (or anything that runs
software) between the reader and the authenticator then couldn't you just
replace the reader with another bit of software that pretends to be a
reader? Where can I get the biometric info required? Police stations
have a large quantity of finger prints, as have practically every surface
you've touched recently...
This exposure, of PIN compromise, is genric in all smartcard products
unless a dedicated PINpad or biometric-sensor equipped readers are used
putting cost of ownership towards $1000 in some cases.
PC/SC doesn't help - as a data interfcae API spec, it excludes human
interface aspects. STIP (Small Terminal Interoperability Platform at
www.stip.org) moves in this direction, but has evolved into many
interoperate with proprietary vendors and proprietary industry standards.
The challenges in putting biometric sensors or PINpads onto cards include
the need to conform to ISO 7816 for form factor, physical resilience etc,
and that the cards are unpowered. Or, someone redesigns the entire
form-factor, user interface model, portability and business model -
something that has previously failed to go anywhere.
Something like a mobile phone or PDA is a good compromise tool to this
overall exposure, imho.
From: Kevin Sheldrake [mailto:kev () electriccat co uk]
Sent: Thursday, 5 August 2004 8:39 PM
To: Toomas Soome; lionel.ferette () belnet be
Cc: vuln () hexview com; full-disclosure () lists netsys com;
bugtraq () securityfocus com
Subject: Re: [Full-Disclosure] Clear text password exposure in Datakey's
tokens and smartcards
Surely if the user is entering a passphrase then the same problem exists
that of effectively eavesdropping that communication from the keyboard?
Ignoring the initial expense for a moment, wouldn't it have made a lot of
sense to include the keypad actually on the cards? Obviously, card
readers would need to be contructed such that the keypad part of the card
would be exposed during use. The keypad security could then rely on the
tamper resistant properties of the rest of the card.
From a costs perspective, I would guess that the actual per-card cost
increase would be minimal if hundreds of millions of these cards were
Lionel Ferette wrote:
Note that this is true for almost all card readers on the market, not
only for Datakey's. Having worked for companies using crypto smart
cards, I have conducted a few risk analysis about that. The conclusion
has always been that if the PIN must be entered from a PC, and the
attacker has means to install software on the system (through directed
viruses, social engineering, etc), the game's over.
The only solution against that problem is to have the PIN entered
using a keypad on the reader. Only then does the cost of an attack
raise significantly. But that is opening another can of worms, because
there is (was?) no standard for card readers with attached pin pad (at
the time, PC/SCv2 wasn't finalised - is it?).
at least some cards are supporting des passphrases to implement secured
communication channels but I suppose this feature is not that widely in
use.... how many card owners are prepared to remember both PIN codes
Kevin Sheldrake MEng MIEE CEng CISSP
Electric Cat (Bournemouth) Ltd
- Re: [Full-Disclosure] Clear text password exposure in Datakey's tokens and smartcards Kevin Sheldrake (Aug 06)