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Security

A New Approach to Mutating Malware 80

mandelbr0t writes "CBC is reporting that researchers at the Penn State University have discovered a new method of fighting malware that better responds to mutations. From the article: 'The new system identifies a host computer with a high rate of homogeneous connection requests, and blocks the offending computer so no worm-infected packets of data can be sent from it.' This is a change from previous methods, which compared suspected viruses against known signatures. Mutations in malware took advantage of the time-delay between the initial infection and the time taken by the anti-virus system to update its known signatures. This new system claims to be able to recognize new infections nearly instantly, and to cancel the quarantine in case of false alarm."
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A New Approach to Mutating Malware

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  • How does it work? (Score:5, Informative)

    by Aryeh Goretsky ( 129230 ) on Friday February 09, 2007 @07:06PM (#17956380) Homepage
    Hello,

    There's not really a lot of information about how Proactive Worm Containment (PWC) works in the article. A quick bit of searching found the Penn State University Cyber Security Lab's home page here [psu.edu] and Professor Peng Liu's home page here [psu.edu] along with the university's press release here [psu.edu], but I did not see any actual articles on PWC.

    A more detailed description would be most welcome, since the press release makes it sound like this is an automated response to quarantining a host which is performing a DDoS, and it is not clear how PWC would differentiate between that and just a very busy server.

    Regards,

    Aryeh Goretsky
  • by Rich ( 9681 ) on Friday February 09, 2007 @07:16PM (#17956526) Homepage
    I read the article, and I'm still wondering what the 'new' part is. The text doesn't mention anything that hasn't been around for ages, is this a bad article or bad research?
  • by Arrogant-Bastard ( 141720 ) on Friday February 09, 2007 @07:18PM (#17956556)
    This idea was discussed in considerable depth on various
    anti-spam lists several years ago. Nearly all hosts on the
    Internet talk to one mail server: the one designated for
    mail submission from the network they're on. (s/one/few/
    for networks large enough to have multiple SMTP gateways.)

    Such systems, if observed suddenly making connections on
    port 25 to hundreds (or more) other mail servers, are almost
    certainly spewing spam. This is particularly true if those
    connections meet certain criteria (e.g. traffic sent before
    waiting for SMTP greeting from remote side, or failure to
    send QUIT before closing connection). Slapping a port 25
    block on such systems at least partially quarantines the
    problem, buying time for more thorough investigation.

    The same could be said of systems observed making hundreds
    of SSH connections (to one destination or many), etc. The
    basic concept is to figure out what "normal" looks like --
    which, granted, may vary with what uses a system normally
    has -- and then do something when things don't look normal.
    "something" could be "log it" or "issue an alert" or "rate-limit
    connections" or "rate-limit traffic" or "block" or some
    combination; the trick is to select an appropriate response
    that does something useful while not making the mechanism
    so twitchy that it trips when it shouldn't.
  • Helloo.... (Score:3, Informative)

    by idontgno ( 624372 ) on Friday February 09, 2007 @07:24PM (#17956634) Journal

    connectionless packet services? [wikipedia.org]

    Or have we forgotten about SQL Slammer [nai.com], which used a UDP vector?

    Unless, with appropriate hand-waving, we are no longer talking about connections patterns and switching the discussion to packet-destination patterns. Which opens up other UDP-based legitimate applications to pre-emptive blockage. Imagine your lag rage when your antivirus whacks your MMO session.

  • Re:How does it work? (Score:2, Informative)

    by EvanED ( 569694 ) <{evaned} {at} {gmail.com}> on Friday February 09, 2007 @07:25PM (#17956648)
    There is a presentation [psu.edu] about it, but it doesn't go into any more detail about the detection occurs than the article.
  • by jofny ( 540291 ) on Friday February 09, 2007 @07:29PM (#17956718) Homepage
    That doesn't work for most machines you'll find on the internet. Network data simply doesn't contain enough information to concistently build a flexible, accurate profile of normal usage. You're either going to miss a significant amount of stuff youd like to catch, or catch so much legit traffic that it's unusable. You might find the right middle ground between them, but it'll be infrequent and coincidental.
  • Re:How does it work? (Score:4, Informative)

    by nuckfuts ( 690967 ) on Saturday February 10, 2007 @01:42AM (#17959894)
    It's trivial to differentiate between outbound and inbound tcp connections. (The first packet has the SYN flag set to begin a three-way handshake). A busy server woould have a lot of connections coming TO it. A bot would have a lot of connections coming FROM it. In the case of other protocols the SRC and DST information in the packets should suffice to determine direction.
  • by Anonymous Coward on Saturday February 10, 2007 @02:36AM (#17960292)
    Don't forget, this comes from the University that only allows 1.5 GB of TCPIP upload/download a week per student.

    Go over that, and your connection is terminated for the year!

    Check out the Bandwidth policy at www.rescom.psu.edu (not sure if accessible off campus)

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