ZDI-11-198: (Pwn2Own) Microsoft Internet Explorer Uninitialized Variable Information Leak Vulnerability
June 14, 2011
-- CVSS: 7.5, (AV:N/AC:L/Au:N/C:P/I:P/A:P)
-- Affected Vendors: Microsoft
-- Affected Products: Microsoft Internet Explorer
-- TippingPoint(TM) IPS Customer Protection: TippingPoint IPS customers have been protected against this vulnerability by Digital Vaccine protection filter ID 11255. For further product information on the TippingPoint IPS, visit:
-- Vulnerability Details: This vulnerability allows remote attackers to leak information on vulnerable installations of Internet Explorer. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.
The specific flaw exists within Internet Explorer that allows malicious users to leak information about the memory layout of an Internet Explorer process. When creating a new 'Option' HTML Element, the 'index' field of the object is not set to zero and can be used to leak the location of the global variable table. This can be used to defeat ASLR or to remove the need for heap spraying while exploiting a remote code execution flaw.
-- Vendor Response: Microsoft has issued an update to correct this vulnerability. More details can be found at:
-- Disclosure Timeline: 2011-03-09 - Vulnerability reported to vendor 2011-06-14 - Coordinated public release of advisory
-- Credit: This vulnerability was discovered by: * Stephen Fewer of Harmony Security (www.harmonysecurity.com)
-- About the Zero Day Initiative (ZDI): Established by TippingPoint, The Zero Day Initiative (ZDI) represents a best-of-breed model for rewarding security researchers for responsibly disclosing discovered vulnerabilities.
Researchers interested in getting paid for their security research through the ZDI can find more information and sign-up at:
The ZDI is unique in how the acquired vulnerability information is used. TippingPoint does not re-sell the vulnerability details or any exploit code. Instead, upon notifying the affected product vendor, TippingPoint provides its customers with zero day protection through its intrusion prevention technology. Explicit details regarding the specifics of the vulnerability are not exposed to any parties until an official vendor patch is publicly available. Furthermore, with the altruistic aim of helping to secure a broader user base, TippingPoint provides this vulnerability information confidentially to security vendors (including competitors) who have a vulnerability protection or mitigation product.
Our vulnerability disclosure policy is available online at:
Follow the ZDI on Twitter: