CVE-2013-0793 in Firefox
Summary
by MITRE
Mozilla Firefox before 20.0, Firefox ESR 17.x before 17.0.5, Thunderbird before 17.0.5, Thunderbird ESR 17.x before 17.0.5, and SeaMonkey before 2.17 do not ensure the correctness of the address bar during history navigation, which allows remote attackers to conduct cross-site scripting (XSS) attacks or phishing attacks by leveraging control over navigation timing.
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Analysis
by VulDB Data Team • 04/26/2017
The vulnerability described in CVE-2013-0793 represents a critical flaw in the address bar validation mechanisms of several Mozilla applications including Firefox, Thunderbird, and SeaMonkey. This security issue stems from the improper handling of address bar content during history navigation operations, creating a window where malicious actors can manipulate the displayed URL and exploit user trust. The flaw specifically affects versions prior to Firefox 20.0, Firefox ESR 17.x before 17.0.5, Thunderbird before 17.0.5, Thunderbird ESR 17.x before 17.0.5, and SeaMonkey before 2.17, indicating a widespread impact across the Mozilla ecosystem. The vulnerability falls under the CWE-79 category of Cross-Site Scripting, specifically manifesting as a client-side vulnerability that exploits the trust users place in the browser's address bar interface.
The technical implementation of this vulnerability exploits the timing control over navigation operations within the browser's history management system. During history navigation, the browser's address bar should consistently validate and display the correct URL to maintain user awareness of their current location. However, the flaw allows attackers to manipulate the timing of navigation events, potentially causing the address bar to display misleading information while the actual content being rendered remains controlled by malicious scripts. This creates a scenario where users may be deceived into believing they are visiting a legitimate website while actually encountering attacker-controlled content. The vulnerability specifically leverages the gap between when navigation events are initiated and when address bar validation occurs, enabling attackers to inject malicious content or manipulate the displayed URL during this temporal window.
The operational impact of this vulnerability extends beyond simple XSS attacks to encompass sophisticated phishing operations that can deceive users into trusting malicious websites. Attackers can exploit this flaw to create convincing fake login pages or malicious content that appears to originate from legitimate domains, as the address bar may display a trusted URL while the actual rendered content is controlled by attacker scripts. This capability significantly amplifies the potential damage of phishing attacks, as users are more likely to trust content displayed under a familiar address bar appearance. The vulnerability affects not only web browsing but also email client functionality through Thunderbird, potentially allowing attackers to create malicious email content that appears legitimate during navigation operations. Organizations using these affected versions face increased risk of credential theft, data exfiltration, and other malicious activities that exploit user trust in the browser interface.
Mitigation strategies for this vulnerability require immediate patching of affected software versions to ensure proper address bar validation during history navigation operations. System administrators should prioritize updating all affected Mozilla applications to their latest secure versions, particularly focusing on the ESR releases for enterprise environments. Additional protective measures include implementing content security policies that restrict navigation timing manipulation, deploying browser security extensions that monitor for suspicious address bar behavior, and educating users about the importance of verifying URLs even when they appear familiar. The vulnerability demonstrates the critical importance of maintaining proper temporal consistency in browser interface validation and highlights the need for robust input sanitization during navigation operations. Organizations should also consider implementing network-level monitoring to detect anomalous navigation patterns that might indicate exploitation attempts, as the timing-based nature of this vulnerability can be challenging to detect through traditional security measures. This vulnerability serves as a reminder of the complex interplay between user interface trust mechanisms and underlying security controls in web browsers.