CVE-2016-5151 in Chrome
Summary
by MITRE
PDFium in Google Chrome before 53.0.2785.89 on Windows and OS X and before 53.0.2785.92 on Linux mishandles timers, which allows remote attackers to cause a denial of service (use-after-free) or possibly have unspecified other impact via a crafted PDF document, related to fpdfsdk/javascript/JS_Object.cpp and fpdfsdk/javascript/app.cpp.
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Analysis
by VulDB Data Team • 09/14/2022
The vulnerability identified as CVE-2016-5151 represents a critical use-after-free flaw within PDFium, the embedded PDF rendering library used by Google Chrome across multiple operating systems. This issue affects Chrome versions prior to 53.0.2785.89 on Windows and OS X, and before 53.0.2785.92 on Linux, demonstrating the widespread nature of the flaw across different platform architectures. The vulnerability specifically manifests in the JavaScript execution environment within PDFium, where improper timer handling creates conditions that allow remote attackers to manipulate memory management processes.
The technical root cause stems from inadequate memory management within the JavaScript engine components of PDFium, particularly in the fpdfsdk/javascript/JS_Object.cpp and fpdfsdk/javascript/app.cpp files. When processing crafted PDF documents containing malicious JavaScript code, the timer mechanisms fail to properly manage object lifecycles, leading to situations where freed memory blocks are accessed or reused. This memory corruption occurs during the execution of JavaScript functions that interact with PDF timer events, creating a scenario where attackers can manipulate the timing and execution flow to trigger use-after-free conditions. The flaw operates at the intersection of memory management and JavaScript execution, leveraging the complex interaction between PDF rendering and scripting capabilities.
The operational impact of this vulnerability extends beyond simple denial of service, as it potentially enables remote code execution or other unspecified security impacts. Attackers can craft malicious PDF documents that, when opened in affected Chrome versions, trigger the use-after-free condition during JavaScript timer execution. This could allow adversaries to execute arbitrary code on victim systems with the privileges of the browser process, potentially leading to complete system compromise. The vulnerability's remote exploitability means that users can be compromised simply by viewing malicious PDF content, making it particularly dangerous in phishing campaigns or compromised websites. The attack surface is broad due to the widespread use of Chrome and PDF documents in enterprise and consumer environments.
Mitigation strategies for CVE-2016-5151 primarily focus on immediate version upgrades to patched Chrome releases, which address the underlying memory management issues in the PDFium library. Organizations should implement comprehensive patch management procedures to ensure all affected systems receive updates promptly. Additional protective measures include deploying PDF content filtering solutions that scan and validate PDF documents before rendering, implementing browser security policies that restrict JavaScript execution in PDF contexts, and utilizing sandboxing technologies to limit potential impact if exploitation occurs. Security professionals should also consider network-based intrusion detection systems that can identify and block known malicious PDF patterns. The vulnerability aligns with CWE-416, which addresses use-after-free conditions, and represents a typical example of how JavaScript engine vulnerabilities in document processing libraries can create significant security risks. This flaw demonstrates the critical importance of proper memory management in complex software systems and highlights the need for thorough security testing of interactive scripting environments within document rendering engines.