CVE-2012-6469 in Web Browser
Summary
by MITRE
Opera before 12.11 allows remote attackers to determine the existence of arbitrary local files via vectors involving web script in an error page.
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Analysis
by VulDB Data Team • 12/21/2021
The vulnerability described in CVE-2012-6469 represents a significant information disclosure flaw in Opera web browsers prior to version 12.11. This vulnerability operates through a sophisticated mechanism that exploits the browser's error handling behavior to reveal whether specific local files exist on the target system. The flaw essentially allows remote attackers to perform reconnaissance activities by crafting malicious web scripts that trigger error pages, which inadvertently expose file system information through their error messages. This type of vulnerability falls under the category of information disclosure, where attackers can gather intelligence about the local environment without direct access to the system.
The technical implementation of this vulnerability involves the manipulation of web script execution within the browser's error page rendering mechanism. When Opera processes certain malformed web content, it generates error pages that contain information about the underlying file system structure. Attackers can exploit this behavior by creating web pages that reference non-existent local files in ways that cause the browser to display error information containing path details or file existence indicators. The vulnerability specifically affects how Opera handles local file references within web contexts, particularly when these references trigger error conditions that are then rendered to the user interface. This flaw demonstrates poor input validation and insufficient sanitization of error messages that could inadvertently leak system information to remote parties.
From an operational perspective, this vulnerability enables attackers to perform reconnaissance activities that could lead to more sophisticated attacks. The ability to determine the existence of arbitrary local files provides attackers with valuable information about the target system's file structure, which could be used to identify sensitive files, system configurations, or potential attack vectors. The impact extends beyond simple information disclosure as it provides attackers with a method to map local file systems remotely, potentially revealing the presence of system binaries, configuration files, or user data that could be targeted in subsequent attacks. This reconnaissance capability significantly lowers the barrier for attackers attempting to exploit other vulnerabilities on the same system, making it a particularly dangerous flaw in the context of web-based attacks.
The vulnerability aligns with CWE-200, which addresses "Information Exposure," and demonstrates characteristics that map to ATT&CK technique T1083, "File and Directory Discovery." This mapping highlights the reconnaissance nature of the flaw and its potential to enable broader attack campaigns. The attack surface is particularly concerning as it requires no special privileges or direct system access to exploit, making it accessible to any remote attacker who can deliver malicious web content to a vulnerable Opera user. Security practitioners should note that this vulnerability represents a classic example of how browser error handling can inadvertently create information leakage channels, emphasizing the importance of careful error message design and input validation in web applications. The remediation approach involves updating to Opera version 12.11 or later, which implements proper sanitization of error messages and improved handling of local file references to prevent such information disclosure scenarios.
This vulnerability serves as a reminder of the complex security considerations involved in browser development, where error handling mechanisms must be carefully designed to avoid leaking system information. The flaw demonstrates how seemingly benign browser functionality can become a security risk when error conditions are not properly sanitized, highlighting the need for comprehensive security testing of error handling paths in web applications. Organizations should prioritize updating vulnerable browser installations and consider implementing additional network-level protections to mitigate the risk of exploitation, particularly in environments where users may encounter untrusted web content.