CVE-2015-0822 in Firefox
Summary
by MITRE
The Form Autocompletion feature in Mozilla Firefox before 36.0, Firefox ESR 31.x before 31.5, and Thunderbird before 31.5 allows remote attackers to read arbitrary files via crafted JavaScript code.
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Analysis
by VulDB Data Team • 03/10/2022
The vulnerability identified as CVE-2015-0822 represents a critical security flaw in the form autocompletion functionality of Mozilla Firefox and Thunderbird browsers. This issue affects versions prior to 36.0 for Firefox, 31.5 for Firefox ESR 31.x, and versions before 31.5 for Thunderbird, creating a significant attack surface that could be exploited by remote threat actors. The flaw specifically resides in how these applications handle autocompletion data for web forms, which could be manipulated through malicious JavaScript code to access sensitive local files on the victim's system.
The technical implementation of this vulnerability stems from insufficient validation and sanitization of form data within the browser's autocompletion system. When users interact with web forms, Firefox and Thunderbird typically store and suggest previously entered values to improve user experience. However, the flaw allows attackers to craft JavaScript code that can manipulate this autocompletion behavior to read arbitrary files from the local filesystem. This occurs because the browser's form autocompletion mechanism fails to properly separate or validate the data being processed, creating a path for unauthorized file access through the browser's JavaScript engine.
The operational impact of this vulnerability extends beyond simple information disclosure, as it could enable attackers to access sensitive files that may contain personal data, credentials, or system configuration information. Attackers could potentially exploit this weakness by embedding malicious JavaScript within web pages that, when loaded in the affected browsers, would trigger the autocompletion feature to read files such as browser history, saved passwords, cookies, or even system files. The remote nature of this attack means that victims could be compromised simply by visiting malicious websites, making it particularly dangerous in phishing campaigns or drive-by download scenarios.
This vulnerability aligns with CWE-200, which addresses "Information Exposure," and specifically relates to improper restriction of operations within a limited environment. The flaw also maps to ATT&CK technique T1059.007, "Command and Scripting Interpreter: JavaScript," as it exploits JavaScript execution capabilities to perform unauthorized file access. Additionally, the issue demonstrates characteristics of privilege escalation through browser-based attacks, as it allows remote code execution in the context of the user's browser session, potentially leading to full system compromise. Organizations should prioritize immediate patching of affected versions and implement network-level protections such as web application firewalls and content filtering to prevent exploitation attempts.
Mitigation strategies should include immediate deployment of security patches for Firefox 36.0, Firefox ESR 31.5, and Thunderbird 31.5, along with comprehensive security awareness training for users to recognize potentially malicious web content. Network administrators should consider implementing browser security policies that limit JavaScript execution and restrict access to potentially dangerous websites. Organizations may also benefit from deploying endpoint protection solutions that can detect and block suspicious JavaScript behavior patterns associated with file access attempts. Regular security audits of browser configurations and user access controls should be conducted to minimize the risk of exploitation, particularly in environments where users may encounter untrusted web content.