RE: Steady increase in ssh scans

From: Lee Brotherston (lee.brotherstonat_private)
Date: Mon Feb 11 2002 - 10:55:05 PST

  • Next message: Adam Manock: "Re: Steady increase in ssh scans"

    | Here's my concern.  With worms like nimda, lion, and others, 
    | sniffing is a major factor in analyzing the worm's 
    | propogation and exploitatoin methods.  An ssh based worm 
    | could take sniffing out of the picture (the attack is over an 
    | encrypted service) and reduce forensic analysis to artifact 
    | examination.
    
    I might be wrong, but the way I understood it, the exploits that surround
    various sshds all take place before an encrypted tunnel is setup.  So you
    can still sniff the network for evidence of the exploit taking place.  What
    you may not be able to do however is track what it does next if the next
    phase takes place over encrypted channels.
    
    In the case of a worm you may find that it exploits the daemon only to run
    some arbitrary code, and does not do a great deal over an ssh tunnel.  If
    this was the case then you would probably see strange behaviour from an
    infected machine, for example it would most likely start scanning other
    machines and trying to overflow their sshd's, again you could pickup this
    activity.
    
    The time at which you might not be able to track it, is if after
    exploitation it uses another means to spread between machines using
    encrypted channels, or it trojans some part of the system, like say the ssh
    client :/
    
    </RANDOM THINKING>
    
      Lee
    
    -- 
    Lee Brotherston  -  IP Security Manager, Easynet Ltd
    http://www.easynet.net/         Phone: +44 20 7900 4444
    
    
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