CVE-2012-3567 in Web Browser
Summary
by MITRE
Opera before 12.00 Beta allows remote attackers to cause a denial of service (memory consumption or application hang) via an IFRAME element that uses the src="#" syntax to embed a parent document.
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Analysis
by VulDB Data Team • 01/15/2018
The vulnerability identified as CVE-2012-3567 represents a significant denial of service flaw affecting Opera web browsers prior to version 12.00 Beta. This issue specifically targets the browser's handling of IFRAME elements when utilizing the src="#" syntax, creating a condition where malicious or malformed web content can trigger excessive resource consumption or application hang states. The vulnerability stems from improper parsing and processing of embedded documents within the browser's rendering engine, particularly when dealing with self-referential URL schemes that reference the parent document itself.
The technical implementation of this vulnerability exploits a recursive reference mechanism within Opera's document embedding system. When the browser encounters an IFRAME element with src="#" attribute, it attempts to load the parent document as if it were a separate resource, creating a potential loop or excessive memory allocation scenario. This flaw operates at the application layer and leverages the browser's internal document management processes, where the IFRAME element's source resolution triggers memory allocation patterns that can escalate uncontrollably. The vulnerability manifests as either gradual memory exhaustion through repeated resource allocation or immediate application hang due to infinite loop conditions in the document loading sequence.
From an operational impact perspective, this vulnerability presents a substantial risk to end users and network administrators who rely on Opera browsers for web browsing activities. Attackers can craft malicious web pages that, when loaded in vulnerable Opera versions, will consume excessive system resources or cause the browser to become unresponsive, effectively rendering the user's browsing session unusable. The attack vector requires only that a user navigate to a specially crafted webpage, making it particularly dangerous in phishing scenarios or when users browse untrusted content. The vulnerability's impact extends beyond simple inconvenience to potential system stability issues, as excessive memory consumption can affect overall system performance and potentially crash other applications running on the same machine.
Security professionals should consider this vulnerability in the context of broader web browser security frameworks and threat modeling. The flaw aligns with CWE-400, which addresses "Uncontrolled Resource Consumption" in software systems, and demonstrates how improper handling of document references can lead to resource exhaustion attacks. From an attacker's perspective, this vulnerability maps to ATT&CK technique T1499.004, which involves "Endpoint Denial of Service" through resource exhaustion, making it a valuable vector for attackers seeking to disrupt user productivity or system availability. The vulnerability also reflects poor input validation practices in browser rendering engines, where external content should not be allowed to trigger internal resource allocation patterns that can spiral out of control. Organizations should prioritize patching affected Opera installations and consider implementing browser security policies that limit the execution of potentially malicious content, particularly in environments where users may encounter untrusted web content.
The remediation approach for CVE-2012-3567 requires immediate deployment of Opera version 12.00 Beta or later, which includes fixes for the IFRAME handling mechanism. System administrators should also consider implementing web filtering solutions that can detect and block malformed IFRAME elements with src="#" attributes, particularly in enterprise environments where user browsing behavior cannot be fully controlled. Regular browser updates and security assessments should be part of standard security protocols to prevent exploitation of similar vulnerabilities that may exist in older browser versions or other web applications.