[ISN] Security through obsolescence

From: InfoSec News (isnat_private)
Date: Thu Jun 06 2002 - 20:12:30 PDT

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    By Robin Miller, NewsForge.com
    Posted: 06/06/2002 at 12:10 GMT
    Here's an interesting way to secure an Internet-connected computer
    against intruders: Make sure the operating system and software it runs
    are so old that current hacking tools won't work on it. This was
    suggested by Brian Aker, one of the programmers who works on
    Linux.com, NewsForge, Slashdot, and other OSDN sites; he runs several
    servers of his own that host a number of small non-profit sites in the
    Seattle area. "I have one box still running a version of Solaris
    that's so old none of the script kiddies can figure it out," Brian
    says. "They tend to focus on the latest and greatest, and don't have
    the slightest idea how to handle my old Sun box."
    Brian points out that some of the most secure Department of Defense
    Web sites -- ones that don't make headlines by getting cracked all the
    time -- run old versions of Mac OS and the venerable WebSTAR server
    suite. "[Mac is] a great operating system for that application," he
    says. "No scripting or remote capability at all, so there's no way for
    them to get in."
    Not only that, the hacker/cracker crowd is fixating, as usual, on the
    latest versions of everything, like Windows 2K/XP, Mac OS X, the most
    recent Linux kernels and BSDs, the newest Solaris, and so on. What fun
    is there in breaking into a system running something so ancient only a
    dad would even consider using it? There's also an obscurity factor to
    consider here, and not the one proprietary software advocates usually
    trot out when discussing security issues.
    True "security through obscurity"
    Most Web site takedowns and system intrusions make use of known
    vulnerabilities in a particular operating system or server software
    package. These vulnerabilities are typically discovered, a little at a
    time, by thousands of bad hackers who poke and prod at systems,
    port-scanning and probing them, sharing the information they gain from
    their (mostly failed) attempts with each other. A million monkeys with
    Internet connections may not reproduce any Shakespeare plays -- they
    need to use old-fashioned typewriters to do that -- but they sure as
    bleep are going to find vulnerabilities in any host they contact
    sooner or later simply by sheer weight of numbers, especially if the
    operating system or software they attack is popular enough that they
    have many instances of it out there to look and poke at. It doesn't
    matter whether the operating system and server software under attack
    is proprietary or Open Source. Sooner or later, with enough monkeys
    scratching at it, every single chink or opening can be discovered and
    Imagine a custom operating system used by only a few servers, running
    server software so oddball that cracking lessons learned on mainstream
    servers don't apply to it at all. Or imagine running a DOS variant or
    an OS like AIX that has never been widely used for Net-attached
    servers but is adequate for handing out simple Web pages and receiving
    responses through online forms and handling email, which are the
    primary tasks performed on most publicly-accessible servers.
    Now imagine your local script kiddie trying to crack a box running an
    operating system and server software he's never seen before, about
    which no information is available in the usual online hacker hangouts.  
    Chances are, he's going to move on to an easier target.
    This is security through obscurity at its finest. Even if the custom
    operating system and server software are Open Source, low-level
    attackers aren't going to bother poring over the code thoroughly
    enough to find its vulnerabilities, and those few who have the skill
    level needed almost certainly have better things to do with their time
    -- like work -- and won't bother.
    Really dumb stuff
    Never forget, most intrusions and defacements exploit really stupid
    administrator or user mistakes, like using "password" as the password
    for remote access or running all kinds of unnecessary services that
    create security holes so big a whale could dive through them. These
    lapses have nothing to do with the operating system or software being
    used. No operating system or application ever written is immune to
    user stupidity. Some just take more stupidity to botch than others,
    you might say. But that's enough about that. Let's go back to talking
    about old operating systems.
    Age before beauty
    One advantage of mature software is that lots of people have already
    tried to crack it and lots of patches have been written. A smart
    sysadmin like Brian, running an ancient version of Solaris, has kept
    up with security updates over the years and has installed all of them
    he has found. What some people might sneer at as "obsolete" software,
    others might call "carefully tested" or "proven." Indeed, Debian Linux
    users often point to the fact that Debian's stable branch does not
    include the latest kernel or software as one of its great strengths;  
    Debian lets others explore the latest and greatest -- and fall victim
    to the latest and greatest exploits -- before all the kinks are worked
    out to the Debian maintainers' satisfaction.
    Note that an awful lot of servers out there are still running on Red
    Hat 6.1 or 6.2, not Red Hat 7.x, and that it takes a long time for the
    latest version of Apache to trickle out into the world full-strength.  
    Because these programs have zero licensing cost attached to updates,
    why would so many sysadmins keep using old versions when new ones no
    doubt offer more and slicker features? Obviously, those sysadmins have
    the same outlook as delivery truck fleet managers who refuse to buy a
    new model during its first year or two in production. They prefer to
    wait until all the kinks are worked out and all the defects and
    maintenance tricks have been discovered and applied by early adopters
    before jumping from the tried and true into something new.
    This is sane behavior for a conservative business manager whether she
    is running a fleet of Web servers or a fleet of trucks -- or even a
    fleet of Web servers for a trucking company. But it may be even more
    sane to hold on to the same servers and trucks even when others sneer
    at them as being old, even if new versions are smoother and easier to
    administer or drive. Quite simply, once you have worked with a piece
    of software or a truck for a number of years, you know its quirks
    inside and out. When it acts up in a subtle way someone not used to it
    might not even notice, long experience with it can point an observant
    sysadmin or mechanic straight to a problem, thereby saving downtime
    and repair costs.
    Because "Total Cost of Ownership" is the big management buzz phrase
    that cuts across all business areas, and anything new requires a
    learning curve, sometimes it is best to just keep on using the old
    whatever as long as it does its job reasonably well.
    At some point -- hopefully before Microsoft stops supporting it --
    Windows NT may be reasonably secure against most common exploits. If
    nothing else, by that time there will be hundreds of thousands of
    sysadmins who have learned how to secure it as hard as possible, even
    if they had to learn some lessons the hard way -- by getting cracked.  
    At the same time, the script kiddies and malicious hackers who ran
    roughshod over NT servers when they first appeared have aged. Most of
    them probably have jobs and responsibilities by now, and aren't
    getting their kicks playing in other people's systems but are busily
    securing ones they run themselves.
    The next generation of bad-kid hackers probably won't mess much with
    NT -- or pre-X Mac OS or Linux pre-2.5 kernels or Apache pre-2.x or
    any of the other operating systems and server applications their
    fathers or older siblings ran "back in the day," while those same
    fathers and older siblings will have piled up endless experience
    securing those old, now-obscure programs, making them harder targets
    than the latest stuff.
    You never read about this kind of "security through obscurity," which
    can just as correctly be called "security through obsolescence."  
    Despite this lack of publicity, it may be as effective a tactic as any
    other, and it can be implemented without spending a dime.
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