CVE-2006-1742 in Thunderbird
Summary
by MITRE
The JavaScript engine in Mozilla Firefox and Thunderbird 1.x before 1.5 and 1.0.x before 1.0.8, Mozilla Suite before 1.7.13, and SeaMonkey before 1.0 does not properly handle temporary variables that are not garbage collected, which might allow remote attackers to trigger operations on freed memory and cause memory corruption.
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Analysis
by VulDB Data Team • 01/20/2025
The vulnerability described in CVE-2006-1742 represents a critical memory safety issue within the JavaScript engine of several Mozilla-based applications including Firefox, Thunderbird, and the Mozilla Suite. This flaw stems from improper handling of temporary variables that should be subject to garbage collection but are instead left in an uninitialized state. The issue affects versions prior to specific security patches where Firefox 1.x before 1.5 and 1.0.x before 1.0.8, Mozilla Suite before 1.7.13, and SeaMonkey before 1.0 all contain this memory management defect. The vulnerability is classified under CWE-466 as the use of double-free or use-after-free conditions, which directly relates to improper handling of memory resources in the JavaScript engine implementation.
The technical nature of this vulnerability allows remote attackers to exploit a memory corruption scenario through specific JavaScript code execution patterns that manipulate temporary variables in the engine's memory management system. When the JavaScript engine processes certain code constructs, it fails to properly manage the lifecycle of temporary variables that are meant to be garbage collected, creating a situation where memory that should be reclaimed remains accessible. This creates a window of opportunity for attackers to craft malicious JavaScript payloads that can trigger operations on memory that has already been freed, leading to unpredictable behavior and potential code execution. The flaw operates at the intersection of JavaScript interpretation and memory management, making it particularly dangerous as it can be exploited through web pages or email content without requiring user interaction beyond normal browsing or email reading activities.
The operational impact of CVE-2006-1742 is significant as it enables remote code execution capabilities that can be leveraged by attackers to compromise user systems. When successfully exploited, the memory corruption can lead to arbitrary code execution, allowing attackers to install malware, steal sensitive information, or take complete control of affected systems. The vulnerability affects a broad range of Mozilla-based applications that were widely used in 2006, making it particularly dangerous as it could impact millions of users across different operating systems including Windows, macOS, and Linux platforms. The exploitation requires no special privileges or user interaction beyond visiting a malicious webpage or opening a specially crafted email message containing malicious JavaScript, making it a highly effective attack vector. Security researchers have noted that this vulnerability is particularly concerning because it operates at the core engine level where JavaScript code is interpreted and executed, providing attackers with direct access to system resources through memory corruption.
Mitigation strategies for this vulnerability focus on immediate patching of affected applications to the latest security releases that contain memory management fixes. Users should immediately upgrade to Firefox 1.5, Thunderbird 1.0.8, Mozilla Suite 1.7.13, or SeaMonkey 1.0, respectively, as these versions contain the necessary fixes to prevent the improper handling of temporary variables. Organizations should implement comprehensive patch management procedures to ensure all affected systems are updated promptly, as this vulnerability has been actively exploited in the wild. Additional protective measures include implementing content filtering solutions, disabling JavaScript in email clients when possible, and employing web application firewalls to detect and block malicious JavaScript payloads. From an operational security perspective, this vulnerability highlights the importance of maintaining up-to-date software versions and demonstrates how memory safety issues in core components can create severe security risks that extend beyond traditional exploitation vectors. The vulnerability also aligns with ATT&CK technique T1059.007 for JavaScript execution, emphasizing the need for proper sandboxing and memory protection mechanisms in browser environments.