CVE-2011-0683 in Web Browser
Summary
by MITRE
Opera before 11.01 does not properly restrict the use of opera: URLs, which makes it easier for remote attackers to conduct clickjacking attacks via a crafted web site.
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Analysis
by VulDB Data Team • 10/13/2021
The vulnerability identified as CVE-2011-0683 affects Opera web browsers prior to version 11.01 and represents a significant security flaw in the browser's handling of opera: URLs. This issue stems from insufficient restrictions on the opera: protocol handler, which is a mechanism used by Opera to execute specific internal functions and navigate to particular browser interfaces. The flaw creates a dangerous pathway for malicious actors to exploit the browser's trust model and manipulate user interactions.
The technical implementation of this vulnerability involves the improper validation of opera: URLs within web pages. When Opera processes these URLs, it fails to adequately verify the origin or context from which they originate, allowing remote attackers to craft malicious websites that can invoke opera: URLs with potentially harmful parameters. This misconfiguration enables attackers to leverage the browser's internal navigation system to redirect users to unintended locations or trigger specific browser functions that should only be accessible through legitimate user interaction.
The operational impact of this vulnerability is particularly concerning as it facilitates clickjacking attacks, a technique where attackers trick users into clicking on elements that appear to be benign but actually perform malicious actions. In the context of Opera browsers, this flaw allows attackers to create deceptive web pages that can manipulate the browser's interface to execute unauthorized operations. The vulnerability essentially undermines the browser's security boundaries by permitting external web content to access and manipulate internal browser functionality that should remain protected from external influence.
This vulnerability aligns with CWE-611, which addresses improper access control in web applications, and specifically relates to the improper restriction of operations within a recognized security boundary. The issue also maps to ATT&CK technique T1059.001, which covers command and scripting interpreter, as the vulnerability enables remote code execution through crafted URLs. The attack vector leverages the browser's trust relationship with its own protocol handlers, creating a pathway for privilege escalation and unauthorized access to browser functions.
The security implications extend beyond simple clickjacking to potentially enable more sophisticated attacks including the exploitation of browser internals, manipulation of user preferences, and unauthorized access to browser features. Attackers could use this vulnerability to redirect users to phishing pages, modify browser settings, or execute operations that would normally require explicit user consent. The vulnerability demonstrates a fundamental flaw in Opera's security architecture where internal browser protocols are not adequately protected from external web page manipulation, creating a persistent risk for users of affected browser versions.
Mitigation strategies for this vulnerability include immediate upgrade to Opera version 11.01 or later, which implements proper restrictions on opera: URL handling. Organizations should also implement web application firewalls and content security policies that can detect and block suspicious opera: URL patterns. Additionally, user education regarding the dangers of clicking on untrusted links and the importance of keeping browsers updated remains crucial. The vulnerability highlights the importance of proper input validation and security boundary enforcement in browser implementations, particularly for protocol handlers that provide access to internal system functions.