CVE-2010-1993 in Web Browser
Summary
by MITRE
Opera 9.52 does not properly handle an IFRAME element with a mailto: URL in its SRC attribute, which allows remote attackers to cause a denial of service (resource consumption) via an HTML document with many IFRAME elements.
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Analysis
by VulDB Data Team • 03/30/2025
The vulnerability described in CVE-2010-1993 represents a classic denial of service weakness in web browser implementations that specifically targets Opera version 9.52. This flaw manifests when the browser encounters HTML documents containing multiple IFRAME elements with mailto: URLs in their SRC attributes, leading to excessive resource consumption that can ultimately result in system unresponsiveness or complete service disruption. The issue stems from Opera's inadequate handling of malformed or maliciously constructed HTML content that exploits the browser's processing of mailto: protocol handlers within iframe contexts.
The technical mechanism behind this vulnerability involves the browser's improper resource management when processing numerous IFRAME elements referencing mailto: URLs. When Opera 9.52 encounters such malformed HTML, it fails to properly limit or terminate the processing of these elements, causing continuous resource allocation and consumption. The vulnerability operates at the application layer of the network stack, specifically within the browser's HTML rendering engine and protocol handler implementation. This behavior aligns with CWE-400, which categorizes unchecked resource allocation as a fundamental weakness in software design that leads to resource exhaustion attacks. The flaw essentially creates a scenario where the browser's memory and processing resources are consumed in an uncontrolled manner, potentially leading to complete system freeze or crash.
From an operational impact perspective, this vulnerability presents significant risks to end users and organizations relying on Opera 9.52 for web browsing activities. Attackers can craft malicious HTML documents containing dozens or even hundreds of IFRAME elements with mailto: URLs, effectively creating a resource consumption attack that can render the browser completely unresponsive. The attack requires minimal technical expertise to execute, making it particularly dangerous as it can be delivered through phishing emails, malicious websites, or compromised web applications. This vulnerability directly maps to ATT&CK technique T1499.004, which covers "Cloud Compute Infrastructure Compromise" through resource consumption attacks, though in this case the attack targets local browser resources rather than cloud infrastructure. The impact extends beyond simple inconvenience, as users may lose access to critical browser functionality, potentially leading to productivity loss and security exposure.
The mitigation strategies for this vulnerability primarily focus on browser updates and user education. The most effective solution involves upgrading to a newer version of Opera that properly handles mailto: URLs within IFRAME elements without consuming excessive resources. Additionally, organizations should implement web filtering solutions that can detect and block HTML content containing suspicious IFRAME patterns. Browser security configurations can be adjusted to limit the number of concurrent IFRAME elements or to disable mailto: protocol handling altogether. Network administrators should consider implementing security policies that restrict access to potentially malicious content and monitor for unusual resource consumption patterns that might indicate exploitation attempts. The vulnerability highlights the importance of proper input validation and resource management in browser implementations, emphasizing the need for robust security testing and continuous vulnerability assessment as outlined in industry standards for secure software development practices.