CVE-2016-1975 in Firefox
Summary
by MITRE
Multiple race conditions in dom/media/systemservices/CamerasChild.cpp in the WebRTC implementation in Mozilla Firefox before 45.0 on Windows might allow remote attackers to cause a denial of service (memory corruption) or possibly have unspecified other impact via unknown vectors.
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Analysis
by VulDB Data Team • 10/11/2024
The vulnerability identified as CVE-2016-1975 represents a critical race condition flaw within the WebRTC implementation of Mozilla Firefox, specifically affecting the CamerasChild.cpp component in the dom/media/systemservices directory. This issue manifests in Firefox versions prior to 45.0 on Windows operating systems, creating a significant security risk that could be exploited by remote attackers to compromise system stability and potentially execute arbitrary code. The race condition occurs during the handling of camera subsystem interactions within the WebRTC framework, where concurrent access to shared resources creates unpredictable behavior patterns that can lead to memory corruption. Such vulnerabilities are particularly dangerous in browser environments where multiple processes and threads interact simultaneously, as they can be leveraged to destabilize the entire application or system.
The technical nature of this vulnerability stems from improper synchronization mechanisms within the WebRTC camera child process implementation. When multiple threads attempt to access shared camera resources simultaneously, the lack of proper locking mechanisms or atomic operations creates opportunities for race conditions to occur. These conditions can result in memory corruption when different threads modify the same memory locations without adequate coordination. The flaw is categorized under CWE-362, which specifically addresses Race Conditions, and falls within the broader category of concurrency-related vulnerabilities that affect multi-threaded applications. The implementation of the CamerasChild.cpp file fails to properly manage concurrent access to camera device handles and associated memory structures, creating potential for attackers to manipulate the timing of operations to trigger the race condition.
The operational impact of CVE-2016-1975 extends beyond simple denial of service scenarios, as the memory corruption potential opens pathways for more sophisticated attacks. Remote attackers could exploit this vulnerability to cause Firefox to crash or become unresponsive, effectively creating a denial of service condition that disrupts legitimate user activities. However, the unspecified other impacts mentioned in the description suggest that the vulnerability may also enable privilege escalation or code execution capabilities. Attackers might leverage the memory corruption to inject malicious code into the browser process or manipulate the execution flow of the WebRTC subsystem. This type of vulnerability aligns with ATT&CK technique T1059, which involves executing malicious code through legitimate system processes, and T1499, which encompasses network denial of service attacks that can be achieved through application-level vulnerabilities.
Mitigation strategies for CVE-2016-1975 primarily focus on immediate software updates and system hardening measures. The most effective remediation involves upgrading to Firefox version 45.0 or later, where the race condition has been addressed through improved synchronization mechanisms and proper resource management. System administrators should implement strict patch management policies to ensure all users are running patched versions of the browser. Additional defensive measures include implementing browser security policies that restrict access to camera and microphone devices, enabling sandboxing features, and monitoring for unusual browser behavior that might indicate exploitation attempts. Network-level protections such as web application firewalls and intrusion detection systems can help identify and block exploitation attempts targeting this vulnerability. The fix implemented by Mozilla involved strengthening the synchronization primitives within the camera child process and ensuring proper handling of concurrent access to shared resources, thereby eliminating the race condition that allowed memory corruption to occur.