Movable Type <= 3.33 XSS Exploit
[Description]
MT (Movable Type) is a Blog software.
MT has a XSS filter to remove scripts from user inputs,
but there are ways to evade the filter using malformed input.
[Affected]
Movable Type <= 3.33
[Exploit]
By the default, Blog readers are allowed to post comments
containing html tags.
Attackers may post malformed comments as below.
1. NULL byte in number entitiy reference.
<A href="javascript[0x00]8;alert();">link</A>
2. Unfinished tag in the tail of comment.
<P><BR style="xss:expression(alert())"
MT's filter fails to sanitize these comments.
Scripts in these comments may run in certain browsers
(maybe in IE ONLY).
[Impact]
- Cookies theft.
- Web pages defacing.
[Solution]
Upgrade MT to the newest version.
Six Apart fixed these problems in v3.34.
[Links]
http://www.sixapart.com/movabletype/beta/distros/MT-3.34-beta-Release-Notes.html
See #46226.
----
teracci2002@xxxxxxxxxxx