CVE-2011-3068 in iOS
Summary
by MITRE
Use-after-free vulnerability in the Cascading Style Sheets (CSS) implementation in Google Chrome before 18.0.1025.151 allows remote attackers to cause a denial of service or possibly have unspecified other impact via vectors related to run-in boxes.
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Analysis
by VulDB Data Team • 01/11/2025
The vulnerability identified as CVE-2011-3068 represents a critical use-after-free flaw within Google Chrome's CSS rendering engine that existed prior to version 18.0.1025.151. This type of vulnerability occurs when a program continues to reference memory locations after they have been freed, creating opportunities for malicious exploitation. The specific context involves the handling of run-in boxes within CSS styling, which are elements that behave as inline content but are rendered as block-level elements. These CSS constructs are particularly complex in their implementation and require careful memory management to prevent corruption.
The technical implementation of this vulnerability stems from improper memory management within Chrome's layout engine when processing CSS run-in boxes. When the browser encounters certain CSS properties that create run-in box elements, the underlying memory allocation and deallocation processes fail to properly track references to these objects. This creates a scenario where freed memory can be accessed or overwritten by subsequent operations, potentially leading to arbitrary code execution or system instability. The flaw is classified under CWE-416 as a Use-After-Free condition, which is a well-documented vulnerability pattern that has been exploited in numerous high-profile security incidents.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as indicated by the description's mention of "possibly have unspecified other impact." Remote attackers can leverage this flaw by crafting malicious web pages that trigger the specific CSS conditions leading to the use-after-free condition. When a user visits such a page, the browser's rendering engine processes the CSS and inadvertently accesses freed memory locations, potentially causing crashes or allowing attackers to execute arbitrary code with the privileges of the browser process. This represents a significant threat vector since it requires no local privileges and can be exploited through standard web browsing activities.
The exploitation of this vulnerability aligns with several techniques documented in the attack framework, particularly those involving memory corruption exploits. Attackers can construct malicious web content that forces Chrome to allocate and deallocate memory structures related to run-in boxes, then manipulate the browser into accessing the freed memory locations. This approach follows common patterns seen in browser exploit development where memory management flaws are leveraged to achieve remote code execution. The vulnerability demonstrates how seemingly innocuous CSS processing can become a critical security risk when proper memory management protocols are not followed, highlighting the importance of thorough code review and testing in complex rendering engines.
Mitigation strategies for CVE-2011-3068 primarily focus on updating to patched versions of Google Chrome, specifically version 18.0.1025.151 or later, which contain the necessary fixes for the memory management issues in CSS processing. Additionally, organizations should implement browser hardening measures including sandboxing, content security policies, and regular security updates to reduce the attack surface. The vulnerability also underscores the importance of following secure coding practices such as proper memory management, input validation, and regular security testing, particularly for complex systems like web browsers that handle untrusted content. Network administrators should consider implementing web filtering solutions and monitoring for suspicious web traffic patterns that might indicate exploitation attempts.