CVE-2011-3099 in Chrome
Summary
by MITRE
Use-after-free vulnerability in the PDF functionality in Google Chrome before 19.0.1084.46 allows remote attackers to cause a denial of service or possibly have unspecified other impact via vectors involving a malformed name for the font encoding.
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Analysis
by VulDB Data Team • 03/24/2021
The vulnerability identified as CVE-2011-3099 represents a critical use-after-free flaw within Google Chrome's PDF rendering engine, specifically affecting versions prior to 19.0.1084.46. This issue resides in the browser's handling of PDF documents and demonstrates how seemingly benign document parsing operations can lead to severe security consequences. The vulnerability manifests when Chrome processes malformed font encoding names within PDF files, creating conditions where memory previously allocated to PDF objects becomes accessible after being freed, enabling potential exploitation by remote attackers.
The technical root cause of this vulnerability aligns with CWE-416, which categorizes use-after-free conditions as a fundamental memory safety issue. When Chrome's PDF parser encounters a malformed name in font encoding, the application fails to properly manage memory allocation and deallocation sequences. The parser allocates memory for font objects during PDF processing but does not adequately validate the structure of font encoding names, leading to scenarios where freed memory blocks are accessed or manipulated. This memory management failure creates opportunities for attackers to craft malicious PDF documents that trigger undefined behavior in the browser's memory subsystem, potentially allowing for arbitrary code execution or complete system compromise.
From an operational perspective, this vulnerability presents significant risks to users who regularly access PDF documents through Chrome browsers. The remote attack vector means that simply opening a malicious PDF file could trigger exploitation without any user interaction beyond normal browsing behavior. The potential impact extends beyond simple denial of service to include unspecified other impacts, which typically encompasses privilege escalation, information disclosure, or full system compromise. Attackers could leverage this vulnerability to execute malicious code with the privileges of the Chrome process, potentially leading to complete system infiltration, especially when combined with other attack vectors or browser exploitation techniques.
The exploitation of this vulnerability aligns with several ATT&CK framework techniques including T1203 (Exploitation for Client Execution) and T1059 (Command and Scripting Interpreter) as attackers could use the compromised browser to execute malicious payloads or establish persistent access. Organizations and individuals should prioritize immediate patching of affected Chrome versions to prevent exploitation, as the vulnerability affects a core browser functionality that millions of users rely upon daily. The remediation process requires updating to Chrome version 19.0.1084.46 or later, which includes memory management fixes and enhanced input validation for PDF font encoding structures.
Security professionals should implement additional protective measures including PDF document sanitization, network-based filtering of suspicious PDF content, and user education regarding the risks of opening untrusted PDF files. The vulnerability demonstrates the importance of robust input validation and memory safety practices in browser applications, particularly those handling complex document formats. Organizations should also consider implementing browser isolation techniques and web application firewalls to provide additional defense layers against similar exploitation attempts. Regular security assessments of browser configurations and automated patch management systems can help prevent exploitation of such vulnerabilities in production environments.