SHA-1 and the Great Cosmic Cryptographic “Off-Switch”

In a slightly perverse way I almost enjoy watching the media reporting and reading the third-party pseudery blogging of people who’ve read [www.schneier.com] – it seems a year cannot now go by without someone saying that “MD5 is dead”, “SHA-1 is dead”, “RSA is dead” … stating some degree of academic justification that is rapidly conflated into a media terror.

The most amusing are the reports themed: weird, possibly asocial academic – generally wrong, since in fact most cryppies are awfully well-rounded – has by arcane means found a big, red, Sneakers-style “circumvent all the world’s cryptography and watch the planes fall out of the sky” mathematical switch.

Not all of them are that bad, but enough are.

Of course this is exactly the same sort of claptrap sometimes spouted by the media with regard to any other topic; the difference being with this one that I have a very good idea what is actually going on.

(sigh)

There is a mote of truth, however – the security industry should never get complacent; back in 1985 Robert Morris (he later of the misguided prank that became The Internet Worm) published “A Weakness in the 4.2BSD UNIX TCP/IP Software” [cm.bell-labs.com] which at the time and for some years afterwards this was considered an “academic” weakness, one that was “too hard to exploit” in the real world.

I even remember hearing people tell me this – but even so, nine or so years after publication, Tsutomu woke up to an unexpected surprise.

So yes: that which can conceived in the field of computing can generally be implemented; but so long as we are all using multiple diverse and and redundant tools from the set of algorithms, systems, and platforms that are available to us, no monster will be able to cut the world off at the knees.

Comments

5 responses to “SHA-1 and the Great Cosmic Cryptographic “Off-Switch””

  1. Mark J Musante
    re: SHA-1 and the Great Cosmic Cryptographic

    I believe it was Robert Morris the Elder who wrote the paper, and Robert Morris the Sprog Seeking Attention who wrote the worm.

  2. alecm
    re: SHA-1 and the Great Cosmic Cryptographic

    That is a common misconception; read the paper cited. RTM – note the T for Tappan – was working at the Labs as an intern of some sort. His dad’s middle initial is different, but I forget what. I’ve met his dad once or twice, while visiting Cambridge University.

    A quick google finds that Schneier backs me up:

    http://www.schneier.com/crypto-gram-0103.html

    <<< The flaw centers around the ability of an attacker to predict TCP/IP sequence numbers (called Initial Sequence Numbers, or ISNs), and to use this as a lever to break into systems. Robert Tappan Morris (the son, not the father; the one who wrote the 1988 Internet worm) first wrote about this type of vulnerability in 1985. It became an occasional hacker tool after that; Kevin Mitnick used a sequence number predictor to break into Tsutumo Shimomura’s computer at the San Diego Supercomputer Center around 1995. >>>

    Funny old thing, life, isn’t it?

  3. Mark J Musante
    re: SHA-1 and the Great Cosmic Cryptographic

    A-ha. Cheers.

  4. Chris Samuel
    Making the theoretical practical

    The quote about the ISN attack as being “too hard to exploit” reminds me of the old quote about l0phtcrack:

    [quote]

    “That vulnerability is completely theoretical.” — Microsoft L0pht, Making the theoretical practical since 1992.

    [/quote]

  5. Chris Samuel
    re: Making the theoretical practical

    Grr, bizzare dropsafe reformatting strikes again – one last attempt..

    “That vulnerability is completely theoretical.” — Microsoft

    L0pht, Making the theoretical practical since 1992.

    hopefully that will be clearer!

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