Re: [PEN-TEST] Detecting the presence of a firewall

From: Mule, Andrew (AMuleat_private)
Date: Mon May 14 2001 - 10:49:14 PDT

  • Next message: Geoghegan, Glyn (ISS London): "RE: [PEN-TEST] Detecting the presence of a firewall"

    True. These ports do provide evidence of the host being a CPFW. However,
    this assumes that mgmt is needed from a public location (ports 256,257,258).
    Any company concerned about corporate network security would not run these
    FW's with external mgmt ports enabled. So the new question is how do you ID
    a CPFW with these ports closed? A good answer, stated below, was NMAP with
    the -O option. This option will spit out something like this:
    
    Host  : X.X.X.X
    OS    : Check Point FireWall-1 4.0 SP-5 (IPSO build)
            Nokia IPSO 3.2-fcs4 releng 783
            NOKIA IPSO 3.2 Running Checkpoint Firewall-1
            Nokia IPSO 3.2-fcs4 releng 783 (FreeBSD Based)
    Ports : 53/tcp     closed      domain                           
            256/tcp    open        rap                              
            257/tcp    closed      set                              
            258/tcp    closed      yak-chat 
    
    Host  : X.X.X.X
    OS    : Nokia IPSO 3.2-fcs4 releng 783
    Ports : 53/tcp     closed      domain                            
            256/tcp    open        rap                              
            257/tcp    open        set                              
            258/tcp    open        yak-chat  
    
    Getting addresses behind a firewall can be difficult. Finding out where the
    web, mail or ftp servers usually point to the external IP address of the FW
    itself since arping is done by the FW for the client. I have been
    experiementing with Firewalk as well as modified TOS fields within the ICMP
    protocol to force identification of internal hosts but have not been
    successful....YET. If anyone has something to add to my madness please do so
    with care.
    
    
    Andrew A Mulé
    
    Network Security Architect
    
    Securify Inc.
    
    PGP: F2D5 54A4 F098 369E AA5E
             A64E 0F6F DE52 13C6 BAC5
    



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