CVE-2011-1456 in Chrome
Summary
by MITRE
Google Chrome before 11.0.696.57 does not properly handle PDF forms, which allows remote attackers to cause a denial of service or possibly have unspecified other impact via unknown vectors that lead to "stale pointers."
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Analysis
by VulDB Data Team • 01/15/2025
The vulnerability identified as CVE-2011-1456 affects Google Chrome versions prior to 11.0.696.57 and relates to improper handling of PDF forms within the browser's rendering engine. This issue manifests when Chrome processes PDF documents containing forms, creating a scenario where memory management flaws can be exploited by remote attackers. The vulnerability specifically involves the handling of stale pointers during PDF form processing, which represents a critical memory corruption issue that can lead to unpredictable behavior in the browser environment.
The technical flaw stems from inadequate memory management when Chrome processes PDF forms, particularly in how the browser handles references to memory locations that have already been freed or invalidated. When a PDF form is processed, the browser maintains pointers to various form elements and their associated data structures. In vulnerable versions, these pointers can become stale, meaning they reference memory locations that are no longer valid or have been reallocated for other purposes. This occurs during the PDF rendering process when form elements are manipulated or when the document structure changes, leading to situations where the browser attempts to access memory through invalid references.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as the unspecified other impacts could potentially include arbitrary code execution or further exploitation opportunities. Remote attackers can craft malicious PDF documents that, when opened in vulnerable Chrome versions, trigger the stale pointer condition. This can result in browser crashes, application instability, or in more severe cases, allow attackers to execute arbitrary code within the browser context. The vulnerability demonstrates a classic memory safety issue that aligns with CWE-466, which addresses the use of stale pointers in software applications. The potential for arbitrary code execution makes this particularly dangerous in environments where users may encounter untrusted PDF content.
From an attack perspective, this vulnerability fits within the broader ATT&CK framework under the technique of "Exploitation for Privilege Escalation" and "Command and Control" activities. The stale pointer condition creates an opportunity for attackers to leverage memory corruption to gain control over the browser process, potentially leading to more extensive compromise of the user's system. The fact that this vulnerability affects PDF form handling means that it can be exploited through common attack vectors such as phishing emails with malicious PDF attachments, compromised websites hosting malicious PDFs, or social engineering campaigns targeting users to open infected documents. Organizations should consider this vulnerability as part of a broader attack surface that includes web browser exploitation and document-based attacks.
Mitigation strategies should focus on immediate remediation through browser updates to Chrome version 11.0.696.57 or later, which contains the necessary patches to address the stale pointer handling in PDF form processing. Additionally, organizations should implement defensive measures such as restricting PDF document handling in enterprise environments, using sandboxing techniques, and deploying web application firewalls that can detect and block malicious PDF content. The vulnerability also underscores the importance of regular security updates and patch management programs, as this issue represents a preventable memory corruption flaw that was addressed through proper software maintenance and security testing procedures.