Re: [ISN] Master Key Copying Revealed

From: InfoSec News (isnat_private)
Date: Tue Jan 28 2003 - 10:37:22 PST

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    Forwarded from: Robert Darlington <bobdat_private>
    I recently reviewed Matt Blaze's paper on Rights Amplification in
    Master-Keyed Mechanical Locks.  While it's very interesting, it's
    nothing new.  Matt very carefully describes 100+ year old techniques
    that every locksmith that has taken an ALOA master keying course
    knows.  When I worked as a locksmith, I had a very interesting
    introduction to this technique and a few others.  We went to the
    annual locksmith convention in Vegas.  While there, we worked out the
    master key code by using 4 or 5 other floor change keys in the hotel.  
    Sometimes this is an easy way to make a quick buck when you explain to
    hotel management just how insecure their locks are.  If you're lucky,
    you score a contract to replace all the locks in the hotel.
    Of course, you fall back to trial and error if you only have one key
    to start with, and to test your newly cut keys you have to try them in
    multiple locks, etc. (Just because 5 different keys fit the lock to
    YOUR room, doesnt mean that a single one will fit the room across the
    hall from you).
    Over the years, I've found that locks only keep out honest people so
    layered security is a good thing.  Nine times out of ten, if the front
    door is locked, the 2nd floor window is open. :)
    Robert E. Darlington III              bobdat_private
    Los Alamos National Laboratory        (505)667-2719
    MS P208
    Los Alamos, NM 87544
    On Thu, 23 Jan 2003, InfoSec News wrote:
    > Forwarded from: William Knowles <wkat_private>
    > January 23, 2003
    > A security researcher has revealed a little-known vulnerability in
    > many locks that lets a person create a copy of the master key for an
    > entire building by starting with any key from that building.
    > The researcher, Matt Blaze of AT&T Labs-Research, found the
    > vulnerability by applying his area of expertise - the security flaws
    > that allow hackers to break into computer networks - to the
    > real-world locks and keys that have been used for more than a
    > century in office buildings, college campuses and some residential
    > complexes.
    > The attack described by Mr. Blaze, which is known by some
    > locksmiths, leaves no evidence of tampering. It can be used without
    > resorting to removing the lock and taking it apart or other
    > suspicious behavior that can give away ordinary lock pickers.
    > All that is needed, Mr. Blaze wrote, is access to a key and to the
    > lock that it opens, as well as a small number of uncut key blanks
    > and a tool to cut them to the proper shape. No special skills or
    > tools are required; key-cutting machines costing hundreds of dollars
    > apiece make the task easier, but the same results can be achieved
    > with a simple metal file.
    > After testing the technique repeatedly against the hardware from
    > major lock companies, Mr. Blaze wrote, "it required only a few
    > minutes to carry out, even when using a file to cut the keys."
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