CVE-2011-3906 in Chrome
Summary
by MITRE
The PDF parser in Google Chrome before 16.0.912.63 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 • 03/19/2021
The vulnerability identified as CVE-2011-3906 represents a critical out-of-bounds read flaw within the PDF parser component of Google Chrome versions prior to 16.0.912.63. This issue resides in the browser's handling of PDF documents and demonstrates how seemingly benign document processing can become a vector for significant security impacts. The vulnerability specifically affects the parsing logic that processes PDF files, where improper input validation leads to memory access violations that can be exploited by remote attackers to disrupt normal browser operations. Such flaws are particularly dangerous in web browsers since they can be triggered through routine document viewing activities, making them ideal candidates for exploitation in targeted attacks.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions where programs access memory locations beyond the bounds of allocated buffers. The flaw occurs when Chrome's PDF parser encounters malformed or specially crafted PDF content that triggers an unexpected memory access pattern. This type of vulnerability typically arises from insufficient bounds checking during parsing operations, where the parser does not adequately validate the structure or content of PDF elements before attempting to read from memory locations. The unspecified vectors mentioned in the description suggest that multiple attack paths could potentially trigger this condition, making the vulnerability more difficult to fully characterize and defend against. The out-of-bounds read condition manifests as a denial of service scenario where the browser process crashes or becomes unresponsive, effectively preventing legitimate users from accessing PDF content.
From an operational impact perspective, this vulnerability creates substantial risks for organizations relying on Chrome as their primary browser for document handling and web access. The denial of service condition can be exploited to disrupt user productivity and potentially serve as a stepping stone for more sophisticated attacks. Attackers could craft malicious PDF files that, when opened in vulnerable Chrome versions, would cause browser crashes or system instability, leading to service disruption for end users. The vulnerability's remote nature means that attackers do not require physical access to target systems, as the flaw can be triggered through web-based PDF documents. This characteristic makes it particularly dangerous in environments where users frequently access untrusted web content or where PDF documents are shared through email or web portals.
The mitigation strategy for CVE-2011-3906 primarily involves updating to Google Chrome version 16.0.912.63 or later, which includes patches addressing the out-of-bounds read condition in the PDF parser. Organizations should implement comprehensive patch management procedures to ensure timely deployment of security updates across all browser installations. Additionally, network administrators can consider implementing web filtering solutions that block access to known malicious PDF sources or employ sandboxing techniques to limit the impact of potential exploitation. Security monitoring should focus on detecting unusual browser crash patterns or memory access violations that might indicate exploitation attempts. The vulnerability demonstrates the importance of robust input validation and memory safety practices in browser components, aligning with ATT&CK technique T1203 for exploitation of web browsers and T1499 for denial of service attacks. Organizations should also consider implementing security awareness training to educate users about the risks of opening PDF documents from untrusted sources and the importance of keeping browser software current with security patches.