ZDI-10-154: Apple Webkit Button First-Letter Style Rendering Remote Code Execution Vulnerability http://www.zerodayinitiative.com/advisories/ZDI-10-154 August 11, 2010 -- CVE ID: CVE-2010-1392 -- Affected Vendors: Apple -- Affected Products: Apple WebKit -- TippingPoint(TM) IPS Customer Protection: TippingPoint IPS customers have been protected against this vulnerability by Digital Vaccine protection filter ID 10148. 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 Apple Safari's Webkit. Authentication is not required to exploit this vulnerability. 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 Webkit's support of the 'first-letter' css style. If a particular container has the first-letter style applied to it, the library will create a dual reference of text associated with the style for rendering. Later upon repainting or style recalculation, the application will access the freed memory which can lead to code execution under the context of the application. -- Vendor Response: Apple states: this issue was fixed in Safari 5.0 http://support.apple.com/kb/HT4196 -- Disclosure Timeline: 2010-06-01 - Vulnerability reported to vendor 2010-08-11 - Coordinated public release of advisory -- Credit: This vulnerability was discovered by: * wushi of team509 -- 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
