Re: Loose source routing for remote host discovery

From: Chris McNab (chris.mcnabat_private)
Date: Fri May 09 2003 - 06:58:49 PDT

  • Next message: Richard Ginski: "Where is a Free Copy of ISO17799?"

    OK,
    
    > What I need is a way to use loose source routing in combination with
    nmap -
    > a way to mangle packets and add loose source routing information to the IP
    > options before nmap's packets are sent out to the wire.
    
    Fragroute will do this for both loose and strict source route & record.
    However you do need each and every device in the chain (i.e. all the routers
    & gateways) to forward your source routed packets (and not strip the IP
    options out). All decent firewalls I know of scrub these options by default,
    and most operating systems don't forward source routed packets.
    
    Recently I've worked a little with Todd MacDermid after playing around with
    two utilities of his:
    
    	lsrscan	http://www.synacklabs.net/projects/lsrscan/
    	lsrtunnel	http://www.synacklabs.net/projects/lsrtunnel/
    
    lsrscan allows you to test gateways and routers to see if they forward
    source-routed packets and reverse the route when routing responses back,
    such as follows:
    
    	# lsrscan 192.168.0.0/24
    	192.168.0.0 does not reverse LSR traffic to it
    	192.168.0.0 does not forward LSR traffic through it
    	192.168.0.1 reverses LSR traffic to it
    	192.168.0.1 forwards LSR traffic through it
    	192.168.0.2 reverses LSR traffic to it
    	192.168.0.2 does not forward LSR traffic through it
    
    You need the routers and firewalls in question to forward LSR traffic
    through them in order to scan and probe hosts using source routed packets.
    It is a bonus if the route is reversed, as you can performing spoofing
    attacks.
    
    The lsrtunnel utility is specific to the spoofing issue that exists when a
    gateway or host is found to reverse the source route, so won't be directly
    useful in your case (when trying to port scan and probe boxes relative to a
    gateway that forwards source routed packets). A good breakdown of the issues
    and supporting information can be found at
    http://www.synacklabs.net/OOB/LSR.html.
    
    A second option you may have when talking about putting stuff through a
    firewall to internal hosts that you know are not properly protected, is to
    encapsulate the data somehow (such as FWZ encapsulation in the case of
    Checkpoint FW-1).
    
    HTH,
    
    Chris
    
    
    Chris McNab
    Technical Director
    
    Matta Security Limited
    18 Noel Street
    London W1F 8GN
    
    Tel: 0870 077 1100
    Web: www.trustmatta.com
    
    
    ---------------------------------------------------------------------------
    Did you know that you have VNC running on your network?
    Your hacker does.
    Plug your security holes.
    Download a free 15-day trial of VAM:
    http://www.securityfocus.com/StillSecure-pen-test
    ----------------------------------------------------------------------------
    



    This archive was generated by hypermail 2b30 : Fri May 09 2003 - 11:48:42 PDT