CVE-2011-2335 in Chrome
Summary
by MITRE
A double-free vulnerability exists in WebKit in Google Chrome before Blink M12 in the WebCore::CSSSelector function.
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Analysis
by VulDB Data Team • 02/13/2024
The double-free vulnerability identified in CVE-2011-2335 represents a critical memory corruption flaw within the WebKit rendering engine that powers Google Chrome browsers prior to the Blink rendering engine transition in version 12. This vulnerability specifically affects the WebCore::CSSSelector function, which is responsible for parsing and processing CSS selectors during web page rendering. The flaw occurs when the browser processes malformed CSS content that triggers improper memory management during the handling of CSS selector objects, creating conditions where memory blocks are freed twice, leading to potential arbitrary code execution.
The technical implementation of this vulnerability stems from inadequate memory management within the CSS selector parsing logic. When WebKit encounters certain malformed CSS structures, the WebCore::CSSSelector function fails to properly track memory allocations and deallocations, resulting in a scenario where a memory block allocated for CSS selector processing is freed twice during the normal execution flow. This double-free condition creates a memory corruption state that can be exploited by malicious actors to manipulate the heap memory layout, potentially allowing for remote code execution. The vulnerability is particularly dangerous because it operates within the core rendering engine where all web content is processed, making it accessible through standard web browsing activities.
The operational impact of this vulnerability extends beyond simple browser crashes, as it provides attackers with a pathway to execute arbitrary code on vulnerable systems. An attacker could craft malicious web pages containing specifically designed CSS content that, when rendered by the vulnerable Chrome browser, triggers the double-free condition. This exploitation could lead to complete system compromise, allowing attackers to install malware, steal sensitive data, or establish persistent access to affected systems. The vulnerability affects all versions of Chrome prior to version 12 where the Blink rendering engine was introduced, making it a widespread concern across many deployed browser installations.
Security professionals should note that this vulnerability aligns with CWE-415, which describes improper double-free conditions in memory management. The attack pattern follows typical exploit methodologies described in the MITRE ATT&CK framework under techniques related to code injection and privilege escalation. Organizations should prioritize immediate patching of affected Chrome installations, as the vulnerability does not require user interaction beyond visiting a malicious website. The remediation process involves updating to Chrome version 12 or later where the Blink rendering engine resolves the underlying memory management issues. Additionally, implementing web application firewalls and content security policies can provide additional defense-in-depth measures to mitigate potential exploitation attempts.