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Microsoft Office Web Components Spreadsheet ActiveX Control RCE

Notification Type:	IBM Internet Security Systems Protection Alert
Notification Date:	July 20, 2009
Notification Version:	1.1

Name:	Microsoft Office Web Components Spreadsheet ActiveX Control RCE
Public disclosure/ In the wild date:	July 13, 2009 0-day exploitation and public vuln disclosure
Aliases:	MS09-043
CVE:	CVE-2009-1136
Description:	A vulnerability in the Microsoft Office Web Components Spreadsheet ActiveX Control can result in remote code execution. This vulnerability was made public upon discovery that it was being exploited in the wild on July 13, 2009.

ISS Coverage

Product	Content Version
Network Sensor 7.0 Proventia A Proventia IPS (G/GX) Server Sensor 7.0 Proventia Multifunction Appliance Proventia Server (Linux)	29.071
Proventia Server (Windows) Proventia Desktop	2415

Propagation Techniques	ISS Protection	Available
remote exploit	JavaScript_NOOP_Sled JavaScript_Unescape_Obfuscation HTML_IE_ActiveX_Loader_Heap_Corruption Script_OWC_Heap	Jul 20, 2009 (updated) Jan 8, 2007 June 9, 2009 Aug 11, 2009
	See other protection details below.

JavaScript_NOOP_Sled triggers on the current in-the-wild samples that have been captured by X-Force. Some variants may also trigger JavaScript_Unescape_Obfuscation because of the obfuscation techniques involved in Web page that requests the control.

If attacks happen in the clear, then you can block the attack with Script_OWC_Heap.

You may be able to block these attacks by monitoring for the ID that names the vulnerable control. However, the attacks X-Force has seen in the wild use the ProgramID, which would block any access to this control whether it was the vulnerable version (typically indicated by the ClassID) or not.

Most ActiveX exploits request a certain ClassID that identifies the specific vulnerable ActiveX control. So, blocking this control based on the ClassID might prevent some copycat attackers from succeeding. Adding the ClassIDs to the HTML_IE_ActiveX_Loader_Heap_Corruption signature would achieve this goal. If customers are currently managing lists of custom ClassIDs using the HTML_IE_ActiveX_Loader_Heap_Corruption signature, it might be worthwhile to add the ClassIDs listed in the Microsoft Advisory (http://www.microsoft.com/technet/security/advisory/973472.mspx) to this signature:

0002E541-0000-0000-C000-000000000046
0002E559-0000-0000-C000-000000000046

Customers can add these ClassIDs using the pam.content.clsid.activexloaderbo.blacklist='<clsid>' tuning parameter. To add more than one ClassID (for example, all of the new killbits listed in the Microsoft Advisory - see References below), use:

pam.content.clsid.activexloaderbo.blacklist.1='<clsid>'
pam.content.clsid.activexloaderbo.blacklist.2 ='<clsid>'

At the time of publication, a non-vulnerable version of this control did not exist. So, creating this rule would block any use of this control, good or bad (as long as it happened in the clear).

Detailed Description

Business Impact:	Plug-ins, like this ActiveX control, are one of the top targets of malicious web exploit toolkit developers. These web exploit toolkits now account for nearly all browser-related exploits seen in the wild. The exploitation of this ActiveX control provides the attacker with the privileges of the end user, which could allow complete control over the targeted endpoint. Although this ActiveX control is not installed by default by any Microsoft operating systems, it is installed along with Microsoft Office and is also included on the Microsoft ISA Server. If the control is not already present on a targeted system, the attacker can request the browser to load the control. In addition to Internet Explorer, this control may also be loaded through Office documents.
*CVSS:	Base Score:		9.3
		Access Vector:	Network
		Access Complexity:	Medium
		Authentication:	None
		Confidentiality Impact:	Complete
		Integrity Impact:	Complete
		Availability Impact:	Complete

	Adjusted Temporal Score:		8.6
		Exploitability:	High
		Remediation Level:	Official Fix
		Report Confidence:	Confirmed
Affected Products:	For a full list of affected versions, see references below.
Technical Description:	The Microsoft Office Web Components Spreadsheet ActiveX control could allow a remote attacker to execute arbitrary code on the system, caused by an error related to the handling of an HTML script. By persuading a victim to visit a malicious Web page, a remote attacker could exploit this vulnerability to corrupt memory and execute arbitrary code on the system with the privileges of the victim.
Remediation:	A patch was made available on Aug., 11, 2009. Customers can also manually set the kill bit for these controls and/or deploy security products to block exploits.

References

XFDB:	http://xforce.iss.net/xforce/xfdb/51452
Microsoft:	http://www.microsoft.com/technet/security/advisory/973472.mspx http://www.microsoft.com/technet/security/bulletin/ms09-043.mspx
SANS:	http://isc.sans.org/diary.html?storyid=6778

Revision History

1.0	Initial publication.
1.1	Updated product coverage information with new Script_OWC_Heap signature and release of Microsoft patch and bulletin.

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