CVE-2012-3566 in Web Browser
Summary
by MITRE
Opera before 12.00 Beta allows user-assisted remote attackers to cause a denial of service (application hang) via JavaScript code that changes a form before submission.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 01/23/2018
The vulnerability identified as CVE-2012-3566 represents a denial of service flaw affecting Opera web browsers prior to version 12.00 Beta release. This security issue manifests when malicious JavaScript code exploits a specific behavioral pattern within the browser's form handling mechanism. The vulnerability operates under the premise that an attacker can craft JavaScript code that manipulates form elements immediately before they are submitted, creating a condition that leads to application hang or unresponsiveness.
The technical flaw resides in Opera's JavaScript engine and form processing subsystem where the browser fails to properly handle concurrent modifications to form elements during the submission lifecycle. When JavaScript code executes to alter form properties, attributes, or structure just prior to submission, the browser's internal state management becomes inconsistent, causing the application to freeze or become unresponsive. This behavior stems from inadequate synchronization mechanisms between the JavaScript execution context and the form submission process, creating a race condition that can be reliably triggered by malicious actors.
From an operational impact perspective, this vulnerability enables remote attackers to perform denial of service attacks against Opera users without requiring any privileged access or complex exploitation techniques. The attack requires only that a user visits a malicious website containing the crafted JavaScript payload, making it particularly dangerous in phishing campaigns or compromised websites. The application hang condition renders the browser unusable until manual intervention occurs, effectively disrupting user productivity and potentially providing attackers with additional opportunities to deliver further malicious payloads or maintain persistent access to compromised systems.
The vulnerability maps to CWE-674, which describes "Uncontrolled Recursion" and falls under the broader category of improper handling of exceptional conditions in software applications. This weakness creates a scenario where the browser's normal execution flow becomes disrupted due to recursive or nested processing conditions that cannot be resolved properly. The attack pattern aligns with ATT&CK technique T1499.004, which covers "Endpoint Denial of Service" through manipulation of application execution flow. Security professionals should note that this vulnerability demonstrates the importance of proper state management and concurrency control in web browser implementations, particularly in JavaScript environments where rapid execution contexts can create complex interaction patterns with underlying application components.
Mitigation strategies should focus on updating to Opera 12.00 Beta or later versions where the vulnerability has been addressed through improved form handling mechanisms and enhanced JavaScript engine protections. Organizations should also implement network-level protections such as web application firewalls and content filtering systems that can detect and block malicious JavaScript patterns. Browser hardening techniques including disabling unnecessary JavaScript features, implementing strict content security policies, and using sandboxing mechanisms can further reduce the attack surface. Additionally, user education regarding suspicious website visits and the importance of keeping browsers updated remains crucial in defending against this type of vulnerability exploitation.