Re: Re[4]: IIS .ASP Remote Buffer Overflow [testing for vulnerable installations]

From: Riley Hassell (rhassellat_private)
Date: Sat Apr 13 2002 - 07:41:42 PDT

  • Next message: Thor Larholm: "RE: Testing Of Windows 2000 and NT4 IIS .ASP Remote Buffer Overfl ow"

    Change http://www.security.nnov.ru/index.asp to /iisstart.asp in the POST
    along with switching HTTP/1.0 -> HTTP/1.1 and the tests should work.
    
    The HTTP version may not matter, but for the sake of making our tests
    environments more similar..
    
    -R
    
    
    ----- Original Message -----
    From: "3APA3A" <3APA3Aat_private>
    To: "Riley Hassell" <rhassellat_private>
    Cc: <vuln-devat_private>
    Sent: Saturday, April 13, 2002 7:17 AM
    Subject: Re[4]: IIS .ASP Remote Buffer Overflow [testing for vulnerable
    installations]
    
    
    > Dear Riley Hassell,
    >
    > I do use telnet sometimes ;)
    >
    > I mean in case of _patched_ IIS it doesn't
    >
    > >> RH> will respond with a new error, I believe it's
    > RH> (0x80004005)<br>Request...
    >
    > but simply shows you a page like it does on GET request... You can try
    >
    > >telnet www.security.nnov.ru 80
    > Trying 195.122.226.28...
    > Connected to ntst.sci-nnov.ru.
    > Escape character is '^]'.
    > POST http://www.security.nnov.ru/index.asp HTTP/1.0
    > Accept: */*
    > Host: www.security.nnov.ru
    > Content-Type: application/x-www-form-urlencoded
    > Transfer-Encoding: chunked
    >
    > 1
    > E
    > 0
    >
    > After hitting enter twice you'll HTML content.
    >
    >
    >
    > --Saturday, April 13, 2002, 5:45:04 PM, you wrote to
    3APA3Aat_private:
    >
    >
    > RH> lets see whats up...
    >
    > RH> Do it first manually. Copy and paste the request into a telnet session
    with
    > RH> the web server. I used the telnet.exe that came along with the machine
    I'm
    > RH> testing. It's running Windows 2000 Server, build 5.00.2195 with SP2
    all the
    > RH> latest hotfixes prior to Q319733.
    >
    > RH> Here it is:
    > RH> ----start
    > RH> POST /iisstart.asp HTTP/1.1
    > RH> Accept: */*
    > RH> Host: hostname-changed.com
    > RH> Content-Type: application/x-www-form-urlencoded
    > RH> Transfer-Encoding: chunked
    >
    > RH> 1
    > RH> E
    > RH> 0
    > RH> ----end
    >
    > RH> If you have troubles,try hitting [enter] a few more times in your
    telnet
    > RH> session after you have pasted the session in. Be patient, IIS may need
     to
    > RH> load the ISAPI filter, this could take several seconds or longer
    depending
    > RH> on the speed of the system.
    >
    > RH> Also make sure you haven't changed your iisstart.asp file, just so we
    have
    > RH> the same test environment.
    >
    > RH> For the app you're writing what particular language are you using?
    > RH> If you're writing an app to check for these, try adding a healthy
    timeout
    > RH> limit for data reads. IIS may need to load the filter so it could take
    a
    > RH> while.
    >
    > RH> If IIS is still not throwing the error, then (if you'd like), send me
    a
    > RH> packet capture of your telnet session and a copy of the iisstart.asp
    file on
    > RH> the machine you're testing. Then I should be able to tell you why it's
    not
    > RH> working from that.
    >
    > RH> There's also the possibility that this vulnerability may have been
    > RH> introduced with a  later version of the IIS related dll releases.
    Maybe a
    > RH> underlying code change, or patch caused this issue. Only speculation
    of
    > RH> course ;)
    >
    > RH> -R
    >
    > RH> Riley Hassell
    > RH> Security Research Associate
    > RH> eEye Digital Security
    >
    > RH> Get up...
    > RH> and light the world on fire.
    >
    > >>
    > >> In my case it produces no error and simply responses with page content
    > RH> after
    > >>
    > >>    "\r\n"
    > >>    "1\r\n"
    > >>    "E\r\n"
    > >>    "0\r\n"
    > >>    "\r\n"
    > >>
    > >>
    > >> RH> It won't overwrite anything mission critical so the dllhost
    shouldn't
    > RH> lock
    > >> RH> up or exit. If you're vulnerable then you'll the following string
    in
    > RH> the
    > >> RH> error message "(0x80004005)<br>Unspecified". When a server is
    patched
    > RH> it
    > >> RH> will respond with a new error, I believe it's
    > RH> (0x80004005)<br>Request...
    > >>
    > >> RH> You can also try putting NULL's in strange places in you request.
    The
    > RH> rollup
    > >> RH> fixes a problem in parsing requests with NULLs. When IIS see's
    > RH> something
    > >> RH> invalid in a request it will error back with "parameter incorrect",
    on
    > RH> an
    > >> RH> unpatched system the responses will vary.
    > >>
    > >>
    > >>
    > >> --
    > >> ~/ZARAZA
    > >> ...без дубинки никогда не принимался он за программирование. (Лем)
    > >>
    > >>
    >
    >
    >
    > --
    > ~/ZARAZA
    > Появился новый тип элементарных частиц - шкварки.
    > Не очень большие, слегка подгоревшие.  (Лем)
    >
    >
    



    This archive was generated by hypermail 2b30 : Sat Apr 13 2002 - 12:17:27 PDT