CVE-2018-5160 in Firefox
Summary
by MITRE
WebRTC can use a "WrappedI420Buffer" pixel buffer but the owning image object can be freed while it is still in use. This can result in the WebRTC encoder using uninitialized memory, leading to a potentially exploitable crash. This vulnerability affects Firefox < 60.
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Analysis
by VulDB Data Team • 03/11/2023
The vulnerability identified as CVE-2018-5160 represents a critical memory safety issue within the WebRTC implementation of Mozilla Firefox browsers. This flaw specifically impacts versions prior to Firefox 60, where the WebRTC subsystem utilizes a "WrappedI420Buffer" pixel buffer for handling video frames during encoding processes. The vulnerability stems from improper memory management practices that allow the underlying image object to be destroyed while still referenced by the WebRTC encoder, creating a scenario where the encoder attempts to access memory that has already been freed or reallocated.
The technical execution of this vulnerability involves a classic use-after-free condition where the WebRTC encoder component maintains references to pixel buffer objects that are subsequently destroyed by the garbage collection or memory management subsystem. When the owning image object is freed, the memory location that previously contained valid pixel data becomes available for reuse, but the encoder continues to reference this now-invalid memory address. This leads to the consumption of uninitialized or corrupted memory contents, which can cause the application to crash or potentially execute arbitrary code depending on the memory state at the time of access. The vulnerability manifests as an exploitable crash condition that could be leveraged by attackers to achieve remote code execution in targeted scenarios.
The operational impact of this vulnerability extends beyond simple browser instability, as it creates potential attack vectors for remote exploitation. Attackers could craft malicious WebRTC sessions or video content that triggers the specific memory management race condition, leading to system compromise through controlled memory corruption. This vulnerability particularly affects users of older Firefox versions who may not have received security updates, making it a significant concern for organizations with legacy browser deployments. The issue demonstrates poor memory lifecycle management practices within the WebRTC implementation, where proper reference counting or object lifecycle management mechanisms were not adequately implemented to prevent premature object destruction while active references exist.
Mitigation strategies for CVE-2018-5160 primarily focus on immediate browser updates to Firefox version 60 or later, which contains the necessary patches to address the memory management flaw. Organizations should implement comprehensive patch management processes to ensure all Firefox installations are updated promptly, as this vulnerability represents a high-severity risk for unpatched systems. Additionally, network administrators should consider implementing browser security policies that enforce automatic updates and restrict access to potentially malicious WebRTC content until systems are properly patched. The vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in software implementations, and could potentially map to ATT&CK technique T1203 for exploitation through browser-based attack vectors. Security teams should monitor for indicators of compromise related to WebRTC-based attacks and implement network segmentation to limit exposure to potentially malicious WebRTC content while ensuring proper patch deployment across all affected systems.