ZDI-11-241: Webkit setAttributes attributeChanged Remote Code Execution Vulnerability http://www.zerodayinitiative.com/advisories/ZDI-11-241 July 27, 2011 -- CVE ID: CVE-2011-0254 -- CVSS: 7.5, (AV:N/AC:L/Au:N/C:P/I:P/A:P) -- Affected Vendors: WebKit -- Affected Products: WebKit -- TippingPoint(TM) IPS Customer Protection: TippingPoint IPS customers have been protected against this vulnerability by Digital Vaccine protection filter ID 11481. For further product information on the TippingPoint IPS, visit: http://www.tippingpoint.com -- Vulnerability Details: This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of the Webkit Library. 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 the NamedNodeMap::setAttributes method defined within the NamedNodeMap.cpp file distributed with WebKit. The code responsible for copying attributes between DOM nodes does not verify that a mutation may have occurred when an attribute's attributeChanged method is called. By crafting a page that deletes instances of that attribute when the above mentioned method is called the code within setAttributes can be made to operate on freed objects. An attacker can take advantage of this by spraying the heap in a way that will not result in null pointers being referenced. This can lead to arbitrary code execution under the context of the user running the browser. -- Vendor Response: WebKit has issued an update to correct this vulnerability. More details can be found at: http://support.apple.com/kb/HT4808 -- Disclosure Timeline: 2011-04-19 - Vulnerability reported to vendor 2011-07-27 - Coordinated public release of advisory -- Credit: This vulnerability was discovered by: * Anonymous -- 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: http://www.zerodayinitiative.com 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: http://www.zerodayinitiative.com/advisories/disclosure_policy/ Follow the ZDI on Twitter: http://twitter.com/thezdi