Bugtraq mailing list archives

Re: Hacking USB Thumbdrives, Thumprint authentication


From: "Eric 'MightyE' Stevens" <mightye-removethis- () mightye org>
Date: Tue, 10 Feb 2004 08:49:50 -0500

Navaneetharangan wrote:

2) With the arrival of optic based fingerprint scanners, the probability
of getting authenticated on latent fingerprints (or by using a lifted
fingerprint) is very minimal.
This is not true, there has been a fair amount of research done on creating false finger print pads from latent fingerprints, which mostly consist of defining the oils left behind with, eg, black printer toner, capturing a high resolution image of the finger print with a digital camera or scanner, touching up the image as necessary in a photo editing suite, printing a negative of the finger print on to transparency, and burning a "circuit" with ultraviolet light (common in the home electronics scene). This makes a reusable mold in to which gelatin can be poured to make a false finger pad which regularly fools fingerprint scanners since it is of similar consistency to human finger print pads. The largest covert advantage of the gelatin approach is that the false pads can be applied almost invisibly over a person's existing finger pads, and in the event of a panic of the operative, destruction of the evidence is easy, simply tear off the false pads with your teeth and consume the gelatin; within seconds there is no more trace as the false pads completely dissolve.

For more information on this, check out Google: http://www.google.com/search?q=defeat+fingerprint+scanner+gelatin

3) And you can use all the ten fingers of yours for authentication; it
need not always be your thumbprint alone.

This is true, and this increases the effort required on the part of the covert operative in order to capture a successful identification, however the underlying problem still exists: once a user's prints are successfully compromised, they have no opportunity to alter their key (finger prints). If my password is guessed, I can change it. If my SSH key is broken, I can change it. If my fingerprints are captured, I have no such opportunity.

-Eric "MightyE" Stevens
To reply to me, please remove "-removethis-" from my email address.
http://lotgd.net -- Slay a dragon... over lunch!


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