WordPress 2.0.1 Multiple Vulnerabilities

2006-02-2800:00:00

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[N]eo [S]ecurity [T]eam [NST]® WordPress 2.0.1 Multiple Vulnerabilities

Program : WordPress 2.0
Homepage: http://www.wordpress.org
Vulnerable Versions: WordPress 2.0.1 & lower ones
Risk: Critical!
Impact: XSS, Full Path Disclosure, Directory Listing

-> WordPress 2.0.1 Multiple Vulnerabilities <-

Description

WordPress is a state-of-the-art semantic personal publishing
platform with a focus on aesthetics, web standards, and usability.
What a mouthful. WordPress is both free and priceless at the same time.

Tested

Tested in localhost & many blogs

The vendor was contacted about some other coding errors that are not
described here, the vendor was noticed about these bugs when this
advisory was published.

<+ Multiple XSS +>
There're multiple XSS in `post comment':

[1] `name' variable is not filtered when it's assigned to `value'
on the `<input>' in the form when the comment it's posted.
[2] Happends the same as [1] with `website' variable.
[3] `comment', this variable only filtered " and ' chars, this makes
possible to use < and >, thus this permit an attacker to inject
any HTML (or script) code that he/she want but without any " or '
character, this only happends if the user that post the comment it's
the admin (any registered kind of `user').

If you (or victim) is a unregistered user, you can use " and ' in your
HTML/script Injection using `name' or `website' variables, but if the
victim is the admin or a registered user these 2 fields described above
aren't availabe in the form so you cannot even give a value to them.
The only remaining option it's to use the `comment' variable but here
we have the problem that we cannot use " or ' in HTML/SCRIPT Injected and
we have to make the admin to post the comment (POST method).

<+ Full path disclosure & Directory listing +>
When I discovered this bug, I reported it to some pepople before
public disclosure, I was noticed that this isn't new and I
decided to look why they haven't patch this bug.

As this bug it isn't patched yet, I tryed to know why and I found
something like this in their forum (I don't know if the person
that posted this was the admin but it gives the explanation):
(Something like the following, it's not textual).
`… these bugs are caused by badly configured .ini file, it's not
a bug generated by the script so it cannot be accepted as a bug of
WordPress…'. This is not an acceptable answer, if you think it is,
a bug caused because of register_globals is Off it's .ini fault and not
the script, they have to be kidding, if they want to make good software,
they have to make as far as the language can, to prevent all bugs.

There're multiple files that don't check if they are been call
directly. This is a problem because they expect that functions
that the script is going to be called to be declared.
This kind of bug it's taken as a Low Risk bug, but it can help
to future attacks.

Exploit

– Cross Site Scripting (XSS)
PoC:
[1] Post a comment with the following values (as unregistered user):
(No possible profit)

Name : "><script>alert("WordPress PoC from");</script>
Mail : [email protected]
Website: "><script>alert("[N]eo[S]ecurity[T]eam www.neosecurityteam.net");</script>
Comment: www.neosecurityteam.net/foro/

The injected HTML code only affects the user that posted it, not others.

[2] This way it's more intresting and useful.
In this case the HTML Injected will stay in the board affecting each person
who see it.
But we have two problems:
[I ]- This comment must be posted by the admin
[II]- We only can use the `comment' field, because the admin form to make
the comment doesn't need the `name' or `website'.
Also the injected code cannot have any " or ' chars.

Here are my solutions:
[I ]- We cannot give to the admin a `malicius' URL to steal the cookie
because it isn't via GET, it's via POST. So the solution it's to
make a copy form of the real one and set the default values to
the corresonding field (`comment') to make the stealing.
Also make the form submit itself when the page loads. Thus, we give
the admin the URL of this form and he/she will post the comment
with the values we set before. :)
[II]- We can only use this field to make the injection, the `big' problem
its that we cannot use " or ' chars wich means that something like
window.location = "http://www.google.com.uy"; won't work.

Here are some real examples:

<script>alert(document.cookie)</script>
<script>alert(String.fromCharCode(80,111,67,32,111,102,32,87,111,114,
100,80,114,101,115,115,32,98,121,32,75,52,80,48,32,102,114,111,109,32,
78,83,84))</script>
<script src=http://www.neosecurityteam.net></script>
<script>document.location = String.fromCharCode(104,116,116,112,58,47,
47,119,119,119,46,110,101,111,115,101,99,117,114,105,116,121,116,101,
97,109,46,110,101,116)</script>

As you can see this bug it's exploitable, it's only knowing a bit
deeper how to do XSS under some conditions. There're more
possibilities than described above, investigate yourself.

– Full path disclosure & Directory Listing
Directory Listing: www.victim.com/wordpress/wp-includes/

Solutions

<+ Cross Site Scripting (XSS) +>
Change lines ~21 of 'wp-comments-post.php' to:
$comment_author = htmlentities(trim($_POST['author']));
$comment_author_email = htmlentities(trim($_POST['email']));
$comment_author_url = htmlentities(trim($_POST['url']));
$comment_content = htmlentities(trim($_POST['comment']));

<+ Full Path Disclosure & Directory Listing +>
In the first line of each vulnerable file you should write:
if (eregi('name_of_the_file.php', $_SERVER['PHP_SELF']))
die('You are not allowed to see this page directly');

References

http://NeoSecurityTeam.net/advisories/Advisory-17.txt

Credits

Discovered by K4P0-> k4p0k4p0[at]hotmail[dot]com

[N]eo [S]ecurity [T]eam [NST]® - http://NeoSecurityTeam.net/

Irc.InfoGroup.cl #neosecurityteam
Questions? (Eng | Spa) -> http://NeoSecurityTeam.net/foro/

Greets

Paisterist
HaCkZaTaN
Link
Daemon21
erg0t
NST Comunity!

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