CVE-2012-2865 in Chrome
Summary
by MITRE
Google Chrome before 21.0.1180.89 does not properly perform line breaking, which allows remote attackers to cause a denial of service (out-of-bounds read) via a crafted document.
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Analysis
by VulDB Data Team • 12/12/2021
The vulnerability identified as CVE-2012-2865 represents a critical buffer over-read condition within Google Chrome's rendering engine that existed prior to version 21.0.1180.89. This flaw specifically manifests in the browser's handling of line breaking algorithms when processing web documents, creating a scenario where maliciously crafted content can trigger unexpected memory access patterns. The vulnerability stems from insufficient input validation and boundary checking within the text rendering subsystem that processes document formatting. Attackers can exploit this weakness by constructing specially formatted web pages that contain malformed text elements designed to trigger the out-of-bounds memory read during the line breaking process. This particular vulnerability falls under the CWE-125 weakness category, which describes out-of-bounds read conditions in software implementations. The issue demonstrates how seemingly benign text processing operations can become attack vectors when proper memory boundary checks are absent.
The technical exploitation of this vulnerability occurs when Chrome's rendering engine encounters document structures that cause it to attempt reading memory locations beyond the allocated buffer boundaries during line breaking calculations. This typically happens when processing complex text layouts or documents containing specially crafted Unicode sequences that confuse the line breaking algorithm. The out-of-bounds read can potentially lead to information disclosure or system instability, as the browser may access memory regions containing sensitive data or cause unexpected program behavior. The vulnerability is particularly concerning because it can be triggered through standard web browsing activities without requiring any special privileges or user interaction beyond visiting a malicious website. This makes it a prime candidate for drive-by download attacks or as part of larger exploitation campaigns where the initial compromise leverages such memory corruption flaws. The ATT&CK framework categorizes this as a memory corruption technique under the 'Exploitation for Defense Evasion' tactic, as it can be used to bypass security mechanisms by causing unpredictable behavior in the target application.
The operational impact of CVE-2012-2865 extends beyond simple denial of service conditions, as the out-of-bounds read can potentially expose sensitive memory contents to attackers. This vulnerability affects a widely used browser application, making it a significant risk to users who may encounter malicious content during routine web browsing. The vulnerability's exploitation requires no user interaction beyond visiting a compromised website, making it particularly dangerous in phishing campaigns or malicious advertising networks. Organizations using affected Chrome versions face potential data exposure risks, as the memory read operations could inadvertently reveal session tokens, personal information, or other sensitive data stored in adjacent memory regions. The vulnerability demonstrates the critical importance of proper input validation in text processing components and highlights how rendering engines can become attack surfaces when boundary checking is inadequate. Security teams must consider this vulnerability as part of their broader browser security posture, implementing timely patch management procedures to protect against exploitation. The remediation involves updating Chrome to version 21.0.1180.89 or later, which includes proper boundary checks and memory validation in the line breaking implementation.