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Cross Site Scripting in Microsoft SharePoint 2007
Tue, 13 Sep 2011 -Irene Abezgauz, Seeker Research Center
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.
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Insecure Redirect in Microsoft Sharepoint
Tue, 13 Sep 2011 -Irene Abezgauz, Seeker Research Center
An Insecure Redirect vulnerability has been identified in Microsoft SharePoint shared infrastructure. This vulnerability allows an attacker to craft links that contain redirects to malicious sites in the source parameter used throughout SharePoint portal.
Seeker Research Center
By Irene Abezgauz September 13th, 2011
CVE-2011-1891This 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.
Click on the screenshot below to maximize it.
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=<script>alert("Seeker")</script>
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.
Seeker Research Center
By Irene Abezgauz September 13th, 2011
This vulnerability was discovered by Seeker™
Overview
An Insecure Redirect vulnerability has been identified in Microsoft SharePoint shared infrastructure. This vulnerability allows an attacker to craft links that contain redirects to malicious sites in the source parameter used throughout SharePoint portal.
The exploitation technique detailed in this document bypasses the cross application redirection restriction which normally limits such redirects restricting access to external sites.
Details
Multiple pages and components in Microsoft Sharepoint use the source parameter to redirect users to a new location after accessing a certain page, such as:
POST /Docs/Lists/Announcements/NewForm.aspx?Source=http%3a%2f%2f127.0.0.1%2fDocs%2fdefault.aspx
In order to avoid cross application redirects (which pose a threat to the system), Microsoft Sharepoint enforces checks on these redirects, and limits them to localhost or 127.0.0.1, or the SharePoint server IP (the IP redirect is only valid if the redirect is to an actual SharePoint page on the server, redirects to localhost or 127.0.0.1 will work regardless of existence of relevant page).
The implementation of this verification, however, is flawed, and can be circumvented by creating hostnames which begin with the string localhost, or 127.0.0.1 even if they are not localhost.
Due to domain naming restrictions the 127.0.0.1 prefix cannot be used in exploitation, as http://127.0.0.1.quotium.com is not a valid domain name - subdomain names cannot be digits only. However, redirects to http://localhost.quotium.com or http://localhostie.quotium.com are valid. The following prefixes can be provided into the Source parameter to exploit this vulnerability:
localhostaaa, localhost.quotium.com, etc.
An attacker can generate an attack by creating a site containing localhost in its name, and crafting a URL which embeds into the source parameter a link that lead to sites outside the current application. Once a victim follows the specially crafted link he indeed arrives at the selected page of the vulnerable SharePoint application. Once the page operation is completed, the user will be redirected to the URL in the source parameter.
Exploit
Sample exploitation of this vulnerability would be crafting the following link:
http://MySharePoint/Docs/Lists/Announcements/NewForm.aspx?Source=http%3a%2f%2flocalhost.quotium.com
It is important to note that in many situations, even if the application does not use the source parameter by default, this parameter can be added manually to the URL, leading to exploitation of this vulnerability.
Affected Systems
Microsoft Sharepoint 2007
Microsoft Sharepoint 2010
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.