On 20 May 2010 15:52, Al <news@xxxxxxxxxxxxx> wrote:
> I agree blacklisting is a flawed approach in general. My approach is to
> strictly confine entry text to a whitelist of benign, acceptable tags. The
But that's not what you've done. You've blacklisted the following patterns:
"\<script\x20",
"\<embed\x20",
"\<object\x20",
'language="javascript"',
'type="text/javascript"',
'language="vbscript\"',
'type="text/vbscript"',
'language="vbscript"',
'type="text/tcl"',
"error_reporting\(0\)",//Most hacks I've seen make certain they turn
of error reporting
"\<?php",//Here for the heck of it.
and allowed everything else. A couple of examples:
You haven't blacklisted <iframe>
<IMG SRC="javascript:alert('XSS');"> would sail straight through that list.
I can't tell from that list alone, but are your checks
case-insensitive? Because <ScRipT> would pass through a case-sensitive
check.
We can go on like this all day, and at the end of it you still won't
be sure you've blacklisted everything.
The first answer at
http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags
is related, also.
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