CVE-2011-4687 in Web Browser
Summary
by MITRE
Opera before 11.60 allows remote attackers to cause a denial of service (CPU and memory consumption) via unspecified content on a web page, as demonstrated by a page under the cisco.com home page.
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Analysis
by VulDB Data Team • 11/28/2021
The vulnerability identified as CVE-2011-4687 affects Opera web browsers versions prior to 11.60, representing a critical denial of service weakness that can be exploited remotely through malicious web content. This vulnerability specifically targets the browser's handling of certain web page elements that trigger excessive resource consumption, leading to system instability and potential unavailability of the affected browser instance. The flaw was demonstrated through content hosted on the cisco.com homepage, highlighting the real-world exploitability of this weakness in legitimate web environments.
The technical nature of this vulnerability stems from Opera's insufficient input validation and resource management when processing certain web page constructs. Attackers can craft malicious web content that, when loaded in the vulnerable browser, causes the application to consume excessive cpu cycles and memory resources. This occurs through improper handling of specific HTML elements or scripting constructs that trigger infinite loops, recursive processes, or memory allocation patterns that the browser cannot properly terminate or limit. The vulnerability operates at the application layer, specifically within the browser's rendering engine and resource management subsystems, making it particularly dangerous as it can be triggered simply by visiting a compromised web page.
The operational impact of CVE-2011-4687 extends beyond mere browser instability, as it can be leveraged to disrupt user productivity and potentially create conditions for more sophisticated attacks. When exploited, the vulnerability causes the affected browser to consume all available system resources, leading to complete system freeze or crash of the browser application. This can result in users losing unsaved work, experiencing system slowdowns, or requiring system restarts to restore normal operation. The vulnerability's remote exploitability means that users need not download any files or interact with malicious content directly - simply visiting a compromised web page is sufficient to trigger the attack vector.
Organizations and individual users affected by this vulnerability should immediately update to Opera version 11.60 or later, which includes patches addressing the resource consumption issues. System administrators should also consider implementing web filtering solutions or browser security extensions that can help detect and block potentially malicious content before it can be rendered by the browser. The vulnerability aligns with CWE-400, which categorizes excessive resource consumption as a significant security weakness, and maps to attack techniques described in the ATT&CK framework under process injection and resource exhaustion categories. Additionally, this vulnerability demonstrates the importance of proper input validation and resource management in web browser implementations, as outlined in various secure coding guidelines and best practices for preventing denial of service conditions in client-side applications.