CVE-2011-2669 in Firefox
Summary
by MITRE
Mozilla Firefox prior to 3.6 has a DoS vulnerability due to an issue in the validation of certificates.
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Analysis
by VulDB Data Team • 04/21/2023
The vulnerability identified as CVE-2011-2669 represents a denial of service flaw in Mozilla Firefox versions prior to 3.6, specifically impacting the certificate validation mechanism within the browser's security infrastructure. This issue stems from insufficient validation procedures that allow malicious actors to craft specially formatted certificates capable of triggering unexpected behavior in the browser's certificate handling routines. The flaw exists in the X.509 certificate processing subsystem where Firefox fails to properly validate certificate structures, particularly when encountering malformed or improperly constructed certificate data. This vulnerability falls under the category of CWE-248, which addresses "Uncaught Exception" conditions in software applications, specifically within the context of cryptographic operations and certificate validation. The root cause lies in the absence of proper input sanitization and boundary checking during certificate parsing operations, creating an exploitable condition that can be leveraged to disrupt normal browser functionality.
The technical exploitation of this vulnerability occurs when Firefox encounters a malformed certificate during the SSL/TLS handshake process or when displaying certificate information to users. The browser's certificate validation code lacks adequate error handling mechanisms to gracefully process invalid certificate structures, causing the application to crash or become unresponsive. Attackers can craft malicious certificates with specific malformed fields or structures that trigger buffer overflows, stack corruption, or other memory management issues within Firefox's certificate parsing code. This vulnerability is particularly concerning because it can be triggered during routine certificate validation operations, making it difficult to distinguish from legitimate security events. The flaw impacts the browser's ability to establish secure connections and can be exploited in man-in-the-middle scenarios where attackers present malicious certificates to victims.
The operational impact of CVE-2011-2669 extends beyond simple browser crashes, affecting overall system availability and user trust in secure communications. When exploited, this vulnerability can cause complete browser termination, forcing users to restart their applications and potentially lose unsaved work. In enterprise environments, this vulnerability can be leveraged to disrupt business operations by targeting specific users or systems where Firefox is the primary browser for accessing secure applications. The vulnerability also has implications for security monitoring systems that rely on Firefox for secure web browsing, as the DoS condition can be used to bypass security controls or disrupt normal operational procedures. Additionally, the vulnerability can be combined with other attack vectors to create more sophisticated exploitation scenarios, potentially leading to privilege escalation or information disclosure in some cases. Organizations using affected Firefox versions face increased risk of service disruption and potential security breaches.
Mitigation strategies for CVE-2011-2669 primarily focus on immediate patching and deployment of Firefox version 3.6 or later, which contains the necessary fixes for certificate validation procedures. System administrators should implement mandatory update policies to ensure all Firefox installations are upgraded to versions containing the security patches. Network administrators can deploy certificate inspection tools to identify and block known malicious certificate patterns, though this approach provides only partial protection. The vulnerability also highlights the importance of maintaining up-to-date security patches across all browser installations, as similar issues may exist in other components of the browser security stack. Organizations should consider implementing browser security policies that enforce secure configuration settings and disable unnecessary certificate validation features that may increase attack surface. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and denial of service through application-level exploits, emphasizing the need for layered security approaches. Regular security assessments should include verification of browser certificate validation functionality to prevent similar vulnerabilities from being overlooked in future security reviews.