CVE-2012-2851 in Chrome
Summary
by MITRE
Multiple integer overflows in the PDF functionality in Google Chrome before 21.0.1180.57 on Mac OS X and Linux, and before 21.0.1180.60 on Windows and Chrome Frame, allow remote attackers to cause a denial of service or possibly have unspecified other impact via a crafted document.
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Analysis
by VulDB Data Team • 05/10/2021
The vulnerability identified as CVE-2012-2851 represents a critical security flaw affecting Google Chrome's PDF rendering capabilities across multiple operating systems. This issue stems from improper handling of integer values within the PDF functionality implementation, creating conditions where maliciously crafted PDF documents can trigger unexpected behavior in the browser's rendering engine. The vulnerability specifically impacts Chrome versions prior to 21.0.1180.57 on macOS and Linux platforms, and before 21.0.1180.60 on Windows systems and Chrome Frame extensions, highlighting the cross-platform nature of the flaw.
The technical root cause of this vulnerability lies in integer overflow conditions that occur when processing PDF documents containing specially crafted numerical values. When Chrome encounters these malformed integers during PDF parsing operations, the system fails to properly validate or constrain the integer values, leading to potential buffer overflows or memory corruption scenarios. This type of vulnerability maps directly to CWE-190, which specifically addresses integer overflow and underflow conditions. The flaw exists within the PDF rendering subsystem where integer variables are used to determine memory allocation sizes or loop iterations, creating opportunities for attackers to manipulate these values and cause system instability.
The operational impact of CVE-2012-2851 extends beyond simple denial of service conditions, presenting potential for more severe consequences including arbitrary code execution. Attackers can craft malicious PDF documents that, when opened in vulnerable Chrome versions, trigger the integer overflow conditions and potentially allow for remote code execution or system compromise. The vulnerability affects the browser's ability to properly parse and render PDF files, creating a vector for exploitation that can be delivered through web pages, email attachments, or other document delivery mechanisms. This attack surface aligns with ATT&CK technique T1203, which covers legitimate programs that are used for execution, as the exploitation leverages the legitimate PDF rendering functionality of the browser.
The exploitation of this vulnerability requires minimal user interaction, as simply opening a malicious PDF document in a vulnerable Chrome version can trigger the integer overflow conditions. This makes the attack vector particularly dangerous in phishing campaigns or malicious website scenarios where users might inadvertently encounter compromised PDF content. The vulnerability affects not just individual users but also enterprise environments where Chrome is widely deployed, potentially creating widespread impact across organizations. Organizations should prioritize immediate patching of affected systems and consider implementing additional security controls such as PDF sandboxing, content filtering, and user education to mitigate the risk of exploitation.
Mitigation strategies for CVE-2012-2851 focus primarily on updating Chrome installations to versions containing the appropriate security patches, which address the integer overflow conditions in the PDF rendering engine. System administrators should also implement network-level controls to block access to known malicious PDF content and consider deploying browser security extensions that provide additional layers of protection. The vulnerability demonstrates the importance of proper input validation and integer handling in security-critical applications, emphasizing the need for developers to implement robust boundary checking and overflow prevention mechanisms. Organizations should also conduct regular security assessments to identify and remediate similar vulnerabilities in other browser components and third-party libraries that may be susceptible to similar integer overflow conditions.