CVE-2011-3963 in Chrome
Summary
by MITRE
Google Chrome before 17.0.963.46 does not properly handle PDF FAX images, which allows remote attackers to cause a denial of service (out-of-bounds read) via unspecified vectors.
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Analysis
by VulDB Data Team • 03/20/2021
The vulnerability identified as CVE-2011-3963 represents a critical security flaw in Google Chrome versions prior to 17.0.963.46 that specifically targets the browser's handling of PDF FAX images. This issue stems from improper validation and processing of malformed PDF content, particularly when the browser attempts to render fax images embedded within PDF documents. The flaw manifests as an out-of-bounds read condition that occurs during the parsing and rendering of PDF files, creating a potential vector for remote exploitation. Such vulnerabilities are particularly dangerous in web browsers where users frequently encounter PDF documents from untrusted sources, making this a significant concern for enterprise and individual users alike.
The technical implementation of this vulnerability resides in Chrome's PDF rendering engine, which fails to properly validate the boundaries and structure of FAX image data within PDF files. When processing PDF documents containing malformed FAX images, the browser's parser attempts to read memory locations beyond the allocated buffer boundaries, resulting in an out-of-bounds read operation. This condition can lead to unpredictable behavior including application crashes, memory corruption, and potentially more severe consequences depending on the execution context. The vulnerability operates at the intersection of PDF parsing logic and memory management within the browser's rendering pipeline, making it particularly challenging to mitigate without comprehensive code review and patching.
From an operational perspective, this vulnerability creates a significant risk for users who regularly access PDF documents from the internet or untrusted sources. The denial of service aspect means that attackers can reliably crash Chrome browser instances, disrupting user productivity and potentially creating opportunities for more sophisticated attacks. The remote nature of the exploit means that users do not need to take any specific action beyond viewing a malicious PDF document, making it particularly dangerous in phishing campaigns or malicious website scenarios. This vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and represents a classic example of how improper input validation in multimedia processing components can lead to system instability and potential privilege escalation opportunities.
Organizations and individuals should prioritize immediate patching of affected Chrome versions to address this vulnerability. The recommended mitigation strategy involves updating to Chrome version 17.0.963.46 or later, which includes fixes for the PDF parsing logic that prevent the out-of-bounds read condition. Security administrators should also consider implementing additional controls such as PDF sandboxing, content filtering, and user education about avoiding untrusted PDF sources. The vulnerability demonstrates the importance of maintaining up-to-date browser software and highlights the need for comprehensive security testing of multimedia processing components. From an ATT&CK framework perspective, this vulnerability could be leveraged as part of initial access or execution phases, potentially enabling more sophisticated attack vectors through browser-based exploitation techniques.