CVE-2011-3666 in Thunderbird
Summary
by MITRE
Mozilla Firefox before 3.6.25 and Thunderbird before 3.1.17 on Mac OS X do not consider .jar files to be executable files, which allows user-assisted remote attackers to bypass intended access restrictions via a crafted file. NOTE: this vulnerability exists because of an incorrect fix for CVE-2011-2372 on Mac OS X.
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Analysis
by VulDB Data Team • 11/28/2021
The vulnerability described in CVE-2011-3666 represents a significant security flaw in Mozilla Firefox and Thunderbird applications on Mac OS X systems. This issue stems from an improper implementation of file execution controls that was introduced as a fix for a previous vulnerability, creating a regression that undermines the security model. The flaw specifically affects versions of Firefox prior to 3.6.25 and Thunderbird prior to 3.1.17, making these versions particularly susceptible to exploitation on Mac operating systems.
The technical nature of this vulnerability lies in the incorrect handling of .jar file execution permissions within the application's security framework. Typically, .jar files are recognized as executable archives that contain Java applets or applications, requiring proper security checks before execution. However, the flawed implementation on Mac OS X systems fails to properly categorize these files as executable, allowing attackers to bypass intended access restrictions. This misclassification creates a pathway where malicious .jar files can be executed without proper security validation, effectively circumventing the application's built-in protection mechanisms.
The operational impact of this vulnerability is particularly concerning as it enables user-assisted remote attackers to exploit the system through crafted file delivery methods. Attackers can leverage this flaw by creating specially crafted .jar files that appear benign but contain malicious code. When these files are opened or processed by the vulnerable applications, they can execute with elevated privileges or access restricted system resources. This vulnerability specifically targets Mac OS X environments, making it a platform-specific concern that requires careful attention from system administrators and security professionals managing these operating systems.
This security issue represents a direct violation of the principle of least privilege and demonstrates poor implementation of file type validation within the application security architecture. The vulnerability's classification aligns with CWE-20, which covers "Improper Input Validation," and specifically relates to improper handling of executable file types in security contexts. From an adversarial perspective, this flaw provides a clear attack vector that aligns with ATT&CK technique T1059, which involves executing malicious code through various application interfaces. The fact that this vulnerability was introduced as a regression from a previous fix for CVE-2011-2372 indicates a lack of proper regression testing and thorough validation of security patches.
The mitigation strategy for this vulnerability requires immediate application of security updates to Firefox and Thunderbird versions that address the .jar file execution handling. System administrators should prioritize patching affected systems and ensure that all users upgrade to versions that properly recognize .jar files as executable content requiring security validation. Additionally, organizations should implement network-level controls to monitor and restrict the delivery of potentially malicious .jar files, particularly in environments where users may not immediately apply security updates. The vulnerability serves as a reminder of the importance of comprehensive testing for security patches and the potential risks introduced by incomplete or incorrect security fixes.