Cross Site Scripting in Microsoft SharePoint 2007

Seeker Research Center
By Irene Abezgauz September 13th, 2011
CVE-2011-1891
This vulnerability was discovered by Seeker™;

Overview

A Cross Site Scripting vulnerability has been identified in Microsoft SharePoint 2007. This vulnerability allows attackers to gain control over valid user accounts, perform operations on their behalf, redirect them to malicious sites, steal their credentials, and more.

Details

The Contact Details Tool Pane web part is vulnerable to cross site scripting attacks in the parameter ctl00$MSOTlPn_EditorZone$Edit0g_7aaa0c6d_72f5_4717_9b22_80188ffdbcde$peopleEditor$hiddenSpanData=

By manipulating an unsuspecting user into submitting a specially crafted form an attacker causes the victim to send the malicious script to the vulnerable SharePoint 2007 instance. The malicious script is then reflected back to the user and executed on his browser.

The Contact Details Tool Pane is an out-of-the-box component, accessible from various locations in SharePoint 2007 in which the Contact Details web-part is present. The exploit in this advisory has been produced when editing Report Center.

Exploit

Sample exploitation of this vulnerability would be crafting the following request:

 POST /Reports/Pages/Default.aspx HTTP/1.1 … ctl00$MSOTlPn_EditorZone$Edit0g_7aaa0c6d_72f5_4717_9b22_80188ffdbcde$peopleEditor$hiddenSpanData=

The request of course contains other parameters required by the page, the vulnerable parameter being the parameter noted above. It seems that when a script is simply placed into the input field there is a client-side encoding of the parameter value, which is insufficient to prevent attacks as directly (not via client) submitted scripts simply do not undergo such validation.

Affected Systems

Microsoft SharePoint 2007

Solution

Microsoft has released a fix for this vulnerability, see http://technet.microsoft.com/security/bulletin/MS11-074 for further information.

Credit

The vulnerability was automatically discovered by Seeker™ – New generation application security testing solution, utilizing ground breaking BRITE™ technology (Behavioral Runtime Intelligent Testing Engine).

Further research and publication was performed by Irene Abezgauz, Product Manager, Seeker Security.

This post is also available in: Anglais