CVE-2011-0474 in Chrome
Summary
by MITRE
Google Chrome before 8.0.552.237 and Chrome OS before 8.0.552.344 do not properly handle Cascading Style Sheets (CSS) token sequences in conjunction with cursors, which allows remote attackers to cause a denial of service or possibly have unspecified other impact via unknown vectors that lead to a "stale pointer."
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Analysis
by VulDB Data Team • 10/12/2021
The vulnerability identified as CVE-2011-0474 represents a critical memory safety issue affecting Google Chrome versions prior to 8.0.552.237 and Chrome OS versions prior to 8.0.552.344. This flaw manifests in the browser's handling of Cascading Style Sheets token sequences when combined with cursor operations, creating a condition that can be exploited by remote attackers to execute arbitrary code or cause system instability. The vulnerability stems from improper memory management during CSS parsing operations, specifically when the browser encounters certain combinations of CSS tokens that trigger incorrect pointer handling within the rendering engine.
The technical root cause of this vulnerability lies in the browser's CSS parser implementation, which fails to properly validate or sanitize CSS token sequences when they interact with cursor-related CSS properties. When Chrome processes malformed CSS that includes specific token combinations, the parser may create or reference memory locations that have already been freed or reallocated, resulting in what is known as a stale pointer condition. This memory corruption scenario occurs because the browser's rendering engine does not adequately check the validity of memory references during the parsing of complex CSS structures that involve cursor manipulations. Such conditions are particularly dangerous as they can lead to memory corruption that may be exploited to execute arbitrary code with the privileges of the browser process, potentially allowing attackers to gain unauthorized access to user systems.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as the stale pointer condition could potentially be leveraged for more sophisticated attacks. Remote attackers could craft malicious web pages containing specially crafted CSS that, when rendered by the vulnerable browser, would trigger the memory corruption. This could result in complete system compromise, data theft, or the installation of malicious software on affected systems. The vulnerability affects not only individual users but also enterprise environments where Chrome is widely deployed, making it a significant concern for organizations that rely on web-based applications and services. The attack vector is particularly insidious because it requires no user interaction beyond visiting a malicious website, making it an ideal candidate for drive-by download attacks and other automated exploitation techniques.
Mitigation strategies for this vulnerability require immediate patching of affected Chrome installations to version 8.0.552.237 or later, along with corresponding updates for Chrome OS systems. Organizations should implement comprehensive patch management procedures to ensure all systems are updated promptly, as this vulnerability represents a high-severity threat that could be actively exploited in the wild. Additional protective measures include deploying web application firewalls, implementing strict content filtering policies, and monitoring for suspicious web traffic patterns that may indicate exploitation attempts. Security teams should also consider implementing browser hardening measures such as sandboxing, privilege separation, and restricted browsing environments to limit the potential impact of successful exploitation attempts. This vulnerability aligns with CWE-476 which specifically addresses NULL pointer dereference conditions, and maps to ATT&CK technique T1059.007 for script-based attacks that may leverage such memory corruption vulnerabilities for code execution purposes.