Advisory: ActiveWeb Contentserver CMS Clientside Filtering of Page Editor Content

RedTeam Pentesting discovered a design vulnerability in the page editor
of the activeWeb contentserver CMS during a penetration test. Filtering
of user content, e.g. to prevent the usage of Javascript code, is done
on the client side. By manipulating the POST request, the filtering can
be circumvented.

### Details

- Product: activeWeb contentserver
- Affected Versions: \<= 5.6.2929
- Fixed Versions: 5.6.2964
- Vulnerability Type: Design Flaw
- Security-Risk: medium
- Vendor-URL: `http://www.active-web.de/aw/home/Produkte/~gf/contentserver/`
- Vendor-Status: informed, fixed version released
- Advisory-URL: `https://www.redteam-pentesting.de/advisories/rt-sa-2007-006`
- Advisory-Status: public
- CVE: CVE-2007-3017
- CVE-URL: `https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-3017`

### Introduction

contentserver is the comprehensive, scalable Content Management System
for professional requirements. It combines editorial system, website
management and development platform for web applications in one package.

(translation of the description on the vendor's homepage)

### More Details

The contentserver CMS provides a WYSIWYG (What You See Is What You Get)
editor to edit articles in the browser. The editor is realised as a Java
applet. As Javascript code is not allowed in articles, the editor
filters any script tags.

When clicking the "save" icon, a POST request to

`https://www.example.com/admin/applets/wysiwyg/rendereditor.asp`

is sent. If one manipulates this request to contain Javascript, one is
returned to the Java applet with the hint that script tags were removed.
But, if the next POST request is manipulated, which goes to the script

`https://www.example.com/admin/worklist/worklist_edit.asp`

Javascript code can be embedded in the article, bypassing any filtering
of the applet.

### Fix

The vulnerability is fixed in release 5.6.2964.

### Security Risk

Editors can embed arbitrary Javascript code in articles. An editor with
malicious intent can use this to exploit any viewers accessing the
website. The Javascript will also be executed in the management
interface when viewing the article preview or editing the article. This
means that an attacker may be able to steal the session cookie of other
editors. The risk of this vulnerability is considered medium, as editors
are normally considered trustworthy.

### History

- 2007-05-23 Problem found during a penetration test
- 2007-05-30 Vendor notified by customer
- 2007-06-01 Vendor called back to discuss next steps and to announce  
  investigation
- 2007-06-29 Vendor confirmed the vulnerability
- 2007-06-29 CVE number assigned
- 2007-07-11 Vendor released fixed version
- 2007-07-13 Advisory released
- 2009-05-08 Updated Advisory URL
The vendor was very cooperative. There was always a competent contact
person available who answered any questions.

### RedTeam Pentesting GmbH

RedTeam Pentesting offers individual penetration tests, short pentests,
performed by a team of specialised IT-security experts. Hereby, security
weaknesses in company networks or products are uncovered and can be
fixed immediately.

As there are only few experts in this field, RedTeam Pentesting wants to
share its knowledge and enhance the public knowledge with research in
security-related areas. The results are made available as public
security advisories.

More information about RedTeam Pentesting can be found at
`https://www.redteam-pentesting.de`.