CVE-2012-2857 in WebKitGTK+
Summary
by MITRE
Use-after-free vulnerability in the Cascading Style Sheets (CSS) DOM implementation in Google Chrome before 21.0.1180.57 on Mac OS X and Linux, and before 21.0.1180.60 on Windows and Chrome Frame, allows remote attackers to cause a denial of service or possibly have unspecified other impact via a crafted document.
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Analysis
by VulDB Data Team • 05/11/2021
The vulnerability identified as CVE-2012-2857 represents a critical use-after-free condition within Google Chrome's CSS Document Object Model implementation across multiple platforms. This flaw exists in versions prior to 21.0.1180.57 for Mac OS X and Linux systems, and before 21.0.1180.60 for Windows systems and Chrome Frame components. The issue stems from improper memory management during CSS DOM processing where freed memory locations are accessed after being deallocated, creating potential exploitation vectors for malicious actors.
The technical nature of this vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in software implementations. When Chrome processes crafted CSS documents, the browser's rendering engine fails to properly track memory references within the CSS DOM structure, leading to scenarios where memory allocated to CSS objects becomes available for reuse while still being referenced by active code paths. This memory corruption occurs during the parsing and execution of malformed CSS content that triggers specific code paths within the browser's internal rendering engine.
From an operational perspective, this vulnerability enables remote attackers to execute either denial of service attacks or potentially achieve more severe consequences including arbitrary code execution. The impact extends beyond simple service disruption as the use-after-free condition can be leveraged to manipulate memory contents, potentially allowing attackers to inject malicious code or escalate privileges within the browser environment. The cross-platform nature of this vulnerability means that organizations running Chrome on multiple operating systems face identical risks, requiring coordinated patch management across all affected platforms.
The exploitation of this vulnerability requires attackers to craft malicious web pages containing specially formatted CSS content that triggers the specific memory management flaw during browser rendering. This typically involves creating CSS rules that cause the browser to allocate and subsequently free memory objects in ways that create dangling pointers. The ATT&CK framework categorizes this as a memory corruption vulnerability that can be leveraged for privilege escalation and code execution within the browser sandbox. Organizations should implement immediate patch management procedures to address this vulnerability, as the window for exploitation remains open for systems running unpatched versions of Chrome. The vulnerability demonstrates the critical importance of proper memory management in browser engines and highlights the need for comprehensive security testing of rendering components that handle user-provided content.