Do ICMP re-directs actually work ?

From: Naveed Anwar (naveedat_private)
Date: Tue Oct 30 2001 - 09:44:18 PST

  • Next message: Ian Lyte: "Using Null Session information from NAT.EXE"

    Hi All
    
    I have just been conducting a test in one of our labs by sending ICMP
    redirects to a Windows 2000 Advanced Server using ICMPUSH. Using a
    sniffer I see the packet successfully leave my machine, then again
    from the target box I see the re-direct arrive. Say for example my
    target machine is called Pepsi, and I tell it to redirect any packets
    for a machine called Fanta to a dead gateway, hence communication to
    Fanta will fail for the lifetime of the redirect.
    
    Now my understanding is that the target server (Pepsi) should now
    have updated its local routing table with respect to the Fanta
    machine. Then from Pepsi I try to ping/telnet/http/ftp etc..(i.e
    establish communication) to Fanta I am able to. The point is since I
    told Pepsi via a redirect to send all traffic for Fanta to a
    blackhole, how is the communication working.
    
    One interesting point is that when I issue a netstat -rn to view the
    routing table, I see no route update from the ICMP redirect. 
    
    After reading Ofir's excellent paper I understand most ICMP
    implementations are OS specific, therefore I guess redirects do not
    work in Win2000 or Linux 6.2 which I also tested..or am I doing
    something horribly wrong?
    
    Thanks
    Naveed
    
    ----------------------------------------------------------------------------
    This list is provided by the SecurityFocus Security Intelligence Alert (SIA)
    Service. For more information on SecurityFocus' SIA service which
    automatically alerts you to the latest security vulnerabilities please see:
    https://alerts.securityfocus.com/
    



    This archive was generated by hypermail 2b30 : Tue Oct 30 2001 - 09:44:19 PST