CVE-2010-2121 in Web Browser
Summary
by MITRE
Opera 9.52 allows remote attackers to cause a denial of service (resource consumption) via JavaScript code containing an infinite loop that creates IFRAME elements for invalid (1) news:// or (2) nntp:// URIs.
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Analysis
by VulDB Data Team • 09/14/2021
The vulnerability identified as CVE-2010-2121 affects Opera version 9.52 and represents a denial of service flaw that can be exploited remotely through JavaScript code execution. This vulnerability specifically targets the browser's handling of IFRAME elements when processing invalid news:// and nntp:// URI schemes, creating a condition where the browser consumes excessive system resources leading to service unavailability.
The technical flaw manifests when JavaScript code containing an infinite loop attempts to create IFRAME elements referencing invalid news:// or nntp:// URIs. These URI schemes are typically associated with news reading protocols and network news transfer protocols respectively, but Opera 9.52 fails to properly handle these invalid references in a resource-efficient manner. The browser's JavaScript engine processes these malformed URI references in a loop, continuously attempting to resolve or handle the invalid connections without proper termination conditions, resulting in escalating resource consumption.
This vulnerability operates under the context of web browser security and represents a classic example of resource exhaustion attacks that can be classified under CWE-400, which describes "Uncontrolled Resource Consumption" or "Resource Exhaustion." The flaw demonstrates how improper input validation and lack of loop termination checks in browser JavaScript engines can lead to system instability. From an operational perspective, this vulnerability allows remote attackers to consume system resources such as memory and processor cycles, potentially leading to complete browser crashes or system slowdowns that affect user productivity and system availability.
The attack vector involves delivering malicious JavaScript code through web pages or web applications that contain the infinite loop construct targeting these specific URI schemes. When a user visits a compromised webpage, the JavaScript executes automatically, triggering the resource consumption behavior without requiring any additional user interaction or privileges. This makes the vulnerability particularly dangerous as it can be exploited through simple web browsing activities, making it a significant concern for users who may encounter such malicious content in regular web surfing.
From a cybersecurity framework perspective, this vulnerability aligns with ATT&CK technique T1499.004, which covers "Endpoint Denial of Service: Resource Exhaustion" and demonstrates how attackers can leverage browser-specific implementation flaws to exhaust system resources. The vulnerability also reflects broader concerns about browser sandboxing and resource management within web browsers, where proper bounds checking and resource limits should prevent such scenarios from occurring. Organizations should implement browser update policies and consider browser hardening measures to mitigate such risks, as the vulnerability affects a specific version of Opera that would have been vulnerable to exploitation without proper patching.
The impact of this vulnerability extends beyond simple resource consumption as it can potentially lead to complete browser crashes, system instability, and degraded user experience. In enterprise environments, this could result in productivity loss and increased support overhead as users encounter browser crashes or system slowdowns. The vulnerability also highlights the importance of proper input validation and resource management in web browser implementations, where developers must ensure that all URI handling operations include appropriate bounds checking and timeout mechanisms to prevent infinite processing loops.
Mitigation strategies should include immediate patching of Opera 9.52 installations to the latest available version, implementing browser security policies that restrict JavaScript execution on untrusted sites, and monitoring for suspicious JavaScript behavior that might indicate attempts to exploit such resource exhaustion vulnerabilities. Additionally, network security controls such as web application firewalls and content filtering solutions can help prevent access to malicious websites containing such exploit code, while regular security assessments should include testing for similar resource exhaustion vulnerabilities in other browser components and web applications.