CVE-2012-5906 in GreenBrowser
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in GreenBrowser 6.1.0117 and 6.1.0216 allow remote attackers to inject arbitrary web script or HTML via (1) the URI in an about: page or (2) the last visited URL in the LastVisitWriteEn function in function.js.
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Analysis
by VulDB Data Team • 02/24/2019
The vulnerability identified as CVE-2012-5906 represents a critical cross-site scripting weakness in GreenBrowser versions 6.1.0117 and 6.1.0216. This flaw resides in the browser's handling of URI parameters within about: pages and the processing of last visited URLs through the LastVisitWriteEn function in function.js. The issue stems from inadequate input validation and sanitization mechanisms that fail to properly escape or filter user-supplied data before rendering it within the browser's interface. Such vulnerabilities typically fall under CWE-79 which specifically addresses Cross-Site Scripting flaws, where improper validation of input data allows malicious scripts to be executed in the context of other users' sessions. The attack vector leverages the browser's own functionality to execute malicious code, making it particularly dangerous as it can bypass traditional security measures that rely on external network boundaries.
The technical exploitation of this vulnerability occurs through two distinct attack paths that demonstrate the browser's insufficient sanitization of user-controlled data. The first path involves manipulating the URI parameter within about: pages, which are typically used for displaying browser information and settings. When an attacker crafts a malicious URI containing script tags or other HTML content, the browser fails to properly escape this input before displaying it to users. The second attack vector targets the LastVisitWriteEn function in function.js, which processes and stores the last visited URL. This function does not adequately sanitize URL parameters before writing them to the browser's internal storage or displaying them in subsequent user interfaces. Both attack vectors exploit the fundamental principle that user-supplied data should never be trusted and must always be validated, filtered, and escaped before being rendered in any user-facing context.
The operational impact of CVE-2012-5906 extends beyond simple script execution as it creates a persistent threat vector that can compromise user sessions and potentially lead to more severe security breaches. When users encounter malicious content through either attack path, they may unknowingly execute scripts that can steal session cookies, redirect them to phishing sites, or perform actions on their behalf. The vulnerability is particularly concerning because it affects browser internals rather than external web pages, meaning that attackers can exploit it even when users are browsing legitimate websites. This characteristic aligns with ATT&CK technique T1059.007 which describes the use of scripting languages for execution, and T1566 which covers social engineering techniques that can be enhanced by browser-based exploits. The persistent nature of the vulnerability means that once a user visits a malicious page, the exploit can remain active until the browser is restarted or the affected functionality is patched.
Mitigation strategies for CVE-2012-5906 require immediate patching of affected GreenBrowser versions to address the root cause of the input sanitization failures. Organizations should implement comprehensive input validation and output encoding mechanisms that follow secure coding practices established in OWASP Top Ten and the Secure Coding Guidelines. The solution must ensure that all user-supplied data is properly escaped before being rendered in any browser interface, particularly within internal pages like about: pages and URL display functions. Additionally, implementing Content Security Policy headers can provide an additional layer of protection by restricting the sources from which scripts can be loaded. Regular security assessments should include testing for similar vulnerabilities in browser extensions and internal browser components, as these areas often contain less rigorous security controls compared to external web applications. The vulnerability highlights the importance of maintaining up-to-date browser software and implementing automated patch management systems to prevent exploitation of known vulnerabilities. Organizations should also consider implementing web application firewalls and monitoring systems that can detect and block suspicious URI patterns that may indicate attempts to exploit XSS vulnerabilities.