why i love xs4all + mediaplayer thingie

From: jelmer (jelmerat_private)
Date: Wed May 07 2003 - 17:57:19 PDT

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    Why i love xs4all rant (you'll probably wanna skip this but i need to get
    this out of my system):
    
        a few weeks back i was unpleasantly suprised by the fact that my
    internet wasn't working
        the support desk employee after making me reset my modem a dozen times
    and tripple checking
        my settings finaly found out that i had an abuse ticket.
        I supposedly portscanned (a harmless process) :S some poor guy who felt
    the need to complain about it. They wouldn't tell me who
        it was when it happened or anything. being the second warning (over a 2
    year!! period) they descided they
        had no other alternative then to shut me down. I am not aware of
    anything i have done wrong, but i am not
        given any option to defend myself against the allergations, I dont just
    randomly portscan people.
    
        In essense you are conficted without even hearing the evidence or being
    apointed a lawyer.
        This is a really scary thought because in essence any of the following
    situations will lead to cancelation of
        your account
    
        You activly seek out flaws in a website, you report them to a website
    owner, he doesn't like this and rather than
        fix the problem notifies your ISP xs4all to complain about it. resulting
    in cancelation of your account.
        You wont even know who complained because and explain the whole thing
    because xs4all grants the complaining
        party anonimity
    
        You get hacked and someone uses your machine to do something nasty
    
        An online chatbuddy asks you to nmap his machine to see if the firewall
    he set up is working properly
        after a while the friendship goes sour and just to piss you off he
    reports the scanning.
    
        someone sends you an email containing all sorts of
        <img src="http://www.mysite.com/login.asp?username=a'or 1=1;--">
        kinda stuff, look xs4all!! he hacked my site , just look at my logs and
    xs4all's connection logs
        will show the connections where made from your ip matching the
    timestamps in the log
    
        probably a dozen other ways are possible, and there's no way to find out
    what has been going on
        this shielding of the sources is ridiculous, what will i do tell the
    world i nmapped him?
        well whoopdiedoo call out the witness protection program
    
        Particularly cute is the other day i see an interview with cor bosman
    telling how xs4all
        founders where titled the hacker thread from holland etc
        I have a 4 letter acronym for him, you figure it out
    
    
    Description :
    
        Windows Media Player allows you to play audio and video files
        locally stored and streamed from the Internet.
        It includes a visualizer, a jukebox, a media guide,
        an Internet radio tuner, and support for
        countless media formats and various external devices.
        There is is a flaw in Windows media player 7 and 8 that allows
        execution of arbitrary code
        Vulnerable versions are shipped by default with
        all recent windows distributions including 98 and 2000 and xp
    
    
    Details :
    
        Windows media player skin (.WMZ) files are automaticly opened by
    internet explorer
        As a security precaution they are placed in a folder with a random name
    similar to this :
    
        C:\Program Files\Windows Media Player\Skins\004B1813
    
        However this can be trivially defeated by setting the following http
    headers.
    
        Content-Disposition: filename=%2e%2e%5cjelmer.wmz
        Content-Type: application/download
    
        <content follows>
    
        %2e%2e%5cjelmer.wmz is the url encoded path ..\jelmer.wmz , windows
    media player urldecodes this and the
        path becomes :
    
        C:\Program Files\Windows Media Player\Skins\004B1813\..\jelmer.wmz
    
        witch is equivilent to
    
        C:\Program Files\Windows Media Player\Skins\jelmer.wmz
    
        witch is a known location on the filesystem, witch is a "very bad thing"
    (tm)
        to make matters worse we could append an urlencoded null byte to the
    file name and "spoof" the extention
        like this
    
    
    "%2e%2e%5c%2e%2e%5c%2e%2e%5c%2e%2e%5cDocuments%20and%20Settings%5CAll%20User
    s%5CStart%20Menu%5CPrograms%5CStartup%5csomefile.exe%00.wmz
    
        witch drops an executable in the windows startup folder (on an english
    xp system)
    
    
    Systems affected :
    
        Both media player 7.1 and 8 are affected by the flaw, 9 proofed
    unaffected
    
    
    Example :
    
        I should have attached a sample exploit
    
    
    Vendor status :
    
        Microsoft was notified 23-03-2003 and has issued a fix the details are
    available at
    
    http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS03-017.asp
        Credit was shared because apperently Jouko reported the same issue at
    aproximatly the same time
    
    Solution :
    
        Update to the latest version of media player
    
    
    
    



    This archive was generated by hypermail 2b30 : Thu May 08 2003 - 08:12:55 PDT