fpf module and packet fragmentation:local/remote DoS.

From: XR Agent (prp_scat_private)
Date: Sat Jun 02 2001 - 13:45:26 PDT

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     ('binary' encoding is not supported, stored as-is)
    Fpf kernel module by |CyRaX| [cyraxat_private] (www.pkcrew.org) alters linux tcp/ip stack to emulate other OS'es against nmap/queso fingerprints using parser by FuSyS that reads nmap-os-fingerprints 
    for os emulation choice.
    
    However, attempts to send fragmented packets to local or remote machine with nmap (-sS -f, -sN -f, -sX -f, -sF -f, -sA -f) or hping (hping -f) using host with loaded fpf.o lead to kernel panic ("Aiee, killing interrupt handle. Kernel panic: Attempted to kill the idle task ! In interrupt handler - not syncing.") if run from console or force immediate reboot if the packet sending tool is run from an xterm. When fpf.o - running machine recieves nmap / hping fragmented packets from remote hosts system freezes.
    
    Security through obscurity was never a pefect solution, but in the current case there is also a hefty price to pay: complete inability of tcp/ip stack of "obscured" machine to deal with packet fragmentation.
    
    Tested on Slackware 7.1 kernel 2.2.16 (i386).
    
    Regards,
    
          _clf3_                               (PrP_Scat_private)
         
          Veneficio, ergo sum.
    
    
    
       
    
    
    
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