CVE-2015-4489 in Firefox
Summary
by MITRE
The nsTArray_Impl class in Mozilla Firefox before 40.0, Firefox ESR 38.x before 38.2, and Firefox OS before 2.2 might allow remote attackers to cause a denial of service (memory corruption) or possibly have unspecified other impact by leveraging a self assignment.
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Analysis
by VulDB Data Team • 10/22/2024
The vulnerability identified as CVE-2015-4489 resides within the nsTArray_Impl class implementation in Mozilla Firefox versions prior to 40.0, Firefox ESR 38.x versions before 38.2, and Firefox OS versions before 2.2. This flaw represents a critical memory safety issue that manifests through improper handling of self-assignment operations within the array implementation. The vulnerability specifically affects the internal memory management mechanisms of the nsTArray_Impl template class which is fundamental to Firefox's data structure handling capabilities.
The technical root cause of this vulnerability stems from inadequate validation during self-assignment scenarios within the nsTArray_Impl class. When an array object attempts to assign itself to itself, the implementation fails to properly handle this edge case, leading to memory corruption that can be exploited by remote attackers. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow and is classified as a memory corruption vulnerability that can potentially lead to arbitrary code execution. The flaw occurs because the self-assignment check is either missing or improperly implemented, allowing the destructor to be called on already-destroyed memory regions or causing double-free conditions.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it can potentially enable remote code execution in certain circumstances. Attackers can leverage this weakness by crafting malicious web content that triggers the problematic self-assignment operation, leading to memory corruption that may result in crashes or more severe consequences. The vulnerability's exploitation potential is enhanced by its location within core Firefox components that are frequently accessed during web browsing operations. According to ATT&CK framework, this represents a privilege escalation vector through code injection techniques, specifically targeting the application's memory management subsystem and potentially enabling arbitrary code execution.
Mitigation strategies for CVE-2015-4489 primarily involve upgrading to patched versions of Firefox and Firefox ESR as specified in the advisory. Organizations should implement immediate patch management protocols to ensure all affected systems are updated. Additionally, browser hardening measures such as implementing content security policies and sandboxing mechanisms can provide additional defense-in-depth layers. The vulnerability demonstrates the critical importance of proper memory management practices in C++ applications, particularly when dealing with complex template-based data structures. Security teams should monitor for similar patterns in other software components and implement comprehensive testing procedures for edge cases including self-assignment scenarios. Regular security assessments and code reviews focusing on memory safety practices are essential to prevent similar vulnerabilities from emerging in future releases.