From: stevenr () mastek com [mailto:stevenr () mastek com]
Sent: Wednesday, June 09, 2004 11:25 AM
To: michaels () phg com au; coley () mitre org; webappsec () securityfocus com
Subject: RE: SQL Injection
I was just bouncing the idea off the group of encoding
blindly. That would convert all HTML tags and so should
mitigate the XSS risk to a large extent (even SQL injection,
right? ). But would also play havoc with my data, specially
since I have non-browser systems reading the data too.
I feel the white list approach would be the only way to go....
From: Michael Silk [mailto:michaels () phg com au]
Sent: Wednesday, June 09, 2004 10:11 AM
To: Steven M. Christey; webappsec () securityfocus com
Subject: RE: SQL Injection
There are many many more possibilities for XSS then simply the
<script> tag, of course it depends on where the resulting string
ends up, but simply replacing the <script> tag is *not* enough.
SQL Injection, of course, can not be be mitigated by way of
replacing "<script>" tags either, you aren't really suggesting
this are you ?
From: Steven M. Christey [mailto:coley () mitre org]
Sent: Wednesday, 9 June 2004 7:52 AM
To: webappsec () securityfocus com
Subject: Re: SQL Injection
BTW, any opinions on if I just encode all input without
checking for any
characters? Say converting all <script> to <script> Can anyone
still do XSS or SQL Injection in that case?
Not that I can think of, but there might be implications if there's a
However... If the routine is being coded in C or another language
that's prone to buffer overflows, then you need to make sure to
account for all the potential quoting when allocating the memory to
hold the resulting string. "Transformation-based" buffer overflows
(my hastily coined term) are starting to become more common. If the
transformation converts a double-quote character to a ""e;", then
an attacker could expand the original string by a factor of 6, which
could have implications for the application itself *or* the back end.
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