Re: Preventing OS Detection

From: Ansar Mohammed (ansarm_at_vistapark.org)
Date: 02/24/04

  • Next message: Thompson, Jimi: "RE: Preventing OS Detection" 
    Date: Tue, 24 Feb 2004 13:22:34 -0400
To: Hernan Marcelo Racciatti <hracciatti@hotmail.com>

    one of the techniques that netcraft uses is the OPTIONS http method to
    determine your web server type

    you can simulate this by telnetting to port 80 on any web server and typing

    OPTIONS * HTTP/1.1
    Host: insert_your_webserver_name_here
    <enter>
    <enter>

    you can prevent IIS from returning this info by using URLScan or any
    other ISAPI based IIS application firewall.

    They determine your uptime by using features described in rfc 1323
    method similat to nmap. Specifically TCP timestamping.
    you can disable this feature by using the follwing kbase article

    http://support.microsoft.com/default.aspx?scid=kb;en-us;224829

    have joy...
    Ansar.
    will hack for food.

    Hernan Marcelo Racciatti wrote:

    >> If I go to http://uptime.netcraft.com and enter my website, Netcraft will
    >> display my web servers OS, determined from the TCP/IP packet. Is there
    >> a way
    >> in the windows registry to prevent Netcraft (or anyone else) from
    >> identifying my OS? On the page http://www.webhostgear.com/36,1.html in
    >> paragraph titled "Netcraft is Watching", it briefly describes that
    >> registry
    >> changes can be made. Can someone please give me some specific registry
    >> changes to prevent others from identifying my web servers OS?
    >
    >
    > Hi,
    >
    > Mmmm.. I think .. firewall is the best option. Edit metabase for change
    > banner's in SMTP and HTTP service (In some cases URLScan and some
    > changes in metabese make an good job too). Respect to TCP/IP settings,
    > all of the TCP/IP parameters are registry values located under the
    > registry key:
    >
    > HKEY_LOCAL_MACHINE
    > \SYSTEM
    > \CurrentControlSet
    > \Services:
    > \Tcpip
    > \Parameters
    >
    > RWIN, MSS
    > ---------------
    > HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
    > (GlobalMaxTcpWindowSize, TcpWindowSize, Tcp1323Opts)
    >
    > MTU
    > ------
    > HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces
    > (MTU)
    >
    > TTL
    > -----
    > HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
    > (DefaullTTL)
    >
    >
    > Note: I recommend test this in NO PRODUCTION server. altering these
    > settings will affect your server's performance in diverse ways. Pleasee
    > care! In the major case one valuer setting is a multiple of other
    > value... mmm a TCP/IP knowledge is very important for this settings
    > function.
    >
    > Some links:
    >
    > http://secinf.net/info/nt/2000ip/tcpipimp.html
    > http://www.speedguide.net/read_articles.php?id=157
    > http://www.seoconsultants.com/articles/1000/security.asp
    > http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/tools/locktool.asp
    >
    > http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/tools/urlscan.asp
    >
    > http://www.petri.co.il/change_the_smtp_banner.htm
    >
    > Good luck!
    >
    > Hernán Marcelo Racciatti
    >
    > [mailto:hracciatti@hotmail.com]
    > [http://www.hernanracciatti.com.ar]
    >
    > _________________________________________________________________
    > Charla con tus amigos en línea mediante MSN Messenger:
    > http://messenger.latam.msn.com/
    >
    >
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  • Next message: Thompson, Jimi: "RE: Preventing OS Detection"

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