CVE-2012-5157 in Chrome
Summary
by MITRE
Google Chrome before 24.0.1312.52 does not properly handle image data in PDF documents, 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 • 05/21/2021
The vulnerability identified as CVE-2012-5157 represents a critical out-of-bounds read flaw within Google Chrome's PDF rendering engine that affected versions prior to 24.0.1312.52. This vulnerability specifically manifests when Chrome processes image data embedded within PDF documents, creating a scenario where maliciously crafted PDF files can trigger unexpected memory access patterns. The issue stems from inadequate input validation and boundary checking mechanisms within the browser's PDF handling components, which fail to properly sanitize image data before processing. From a cybersecurity perspective, this vulnerability exemplifies the inherent risks associated with complex multimedia document processing within web browsers, where the intersection of multiple parsing layers creates numerous potential attack vectors. The flaw operates at the intersection of software security and memory safety, where improper bounds checking leads to memory access violations that can be exploited remotely.
The technical implementation of this vulnerability involves Chrome's PDF plugin or built-in PDF viewer attempting to parse image data from malicious PDF documents without adequate validation of image dimensions, data structures, or memory boundaries. When encountering malformed or crafted image data, the parsing routine executes an out-of-bounds memory read operation, which can result in unpredictable behavior including application crashes, memory corruption, or potentially more severe exploitation outcomes. This type of vulnerability falls under the CWE-129 category of "Improper Validation of Array Index" and aligns with ATT&CK technique T1203, which involves the use of web browsers for initial access and execution. The vulnerability demonstrates how seemingly benign document processing functionality can become a vector for system compromise, particularly when dealing with complex file formats like PDFs that contain multiple embedded data types.
From an operational standpoint, this vulnerability presents significant risk to organizations relying on Chrome as their primary browser for document handling and web access. Remote attackers can exploit this weakness by delivering malicious PDF documents through various attack vectors including email attachments, compromised websites, or malicious file sharing platforms. The denial of service impact can effectively disrupt user productivity and create opportunities for more sophisticated attacks if the vulnerability is chained with other exploits. Organizations may experience widespread service disruption as users encounter browser crashes when opening legitimate PDF documents that contain embedded malicious content, or when encountering PDFs from untrusted sources. The vulnerability's remote exploitability means that no user interaction beyond opening the PDF document is required, making it particularly dangerous in enterprise environments where PDF documents are frequently shared and accessed.
Mitigation strategies for CVE-2012-5157 primarily involve immediate patching of Chrome installations to version 24.0.1312.52 or later, which contains the necessary fixes for proper image data validation and boundary checking. Organizations should implement comprehensive browser update policies and consider deploying automated patch management solutions to ensure all systems remain current with security fixes. Additional protective measures include implementing PDF document filtering and sandboxing mechanisms, deploying web application firewalls that can detect and block malicious PDF content, and establishing user education programs to avoid opening suspicious PDF attachments. Security teams should also consider network-based detection rules that monitor for PDF-related traffic patterns that might indicate exploitation attempts. The vulnerability serves as a reminder of the importance of maintaining up-to-date software and the critical need for robust input validation in multimedia processing components, particularly those handling complex file formats that are commonly used in business and enterprise environments.