CVE-2018-18503 in Firefox
Summary
by MITRE
When JavaScript is used to create and manipulate an audio buffer, a potentially exploitable crash may occur because of a compartment mismatch in some situations. This vulnerability affects Firefox < 65.
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Analysis
by VulDB Data Team • 05/08/2020
This vulnerability represents a critical memory safety issue affecting Firefox browsers version 65 and earlier, where improper handling of audio buffer manipulation through JavaScript can lead to exploitable crashes. The flaw manifests when JavaScript code interacts with audio buffer objects, creating conditions where memory compartments become misaligned during buffer operations. Such compartment mismatches typically occur in the interaction between different JavaScript execution contexts and the underlying audio processing subsystem, creating potential avenues for arbitrary code execution. The vulnerability stems from insufficient validation of audio buffer operations within Firefox's JavaScript engine, specifically affecting the garbage collection and memory management processes when audio data is manipulated dynamically. This issue falls under the broader category of memory corruption vulnerabilities that can be exploited to bypass security mitigations such as address space layout randomization and data execution prevention mechanisms.
The technical exploitation of this vulnerability leverages the compartment mismatch to potentially execute malicious code within the browser's memory space, allowing attackers to manipulate audio buffer objects in ways that cause memory corruption. When JavaScript creates audio buffers and performs operations on them, the browser's internal memory management system may fail to properly validate the compartment boundaries between different execution contexts. This mismatch can lead to memory addresses being improperly accessed or overwritten, creating opportunities for attackers to inject and execute arbitrary code. The vulnerability specifically impacts Firefox's audio processing pipeline where JavaScript audio APIs interact with native audio buffer objects, creating a potential attack surface that aligns with common exploitation patterns documented in the attack pattern taxonomy. The issue demonstrates characteristics consistent with heap-based buffer overflow conditions that have been previously catalogued in cybersecurity threat intelligence databases.
The operational impact of this vulnerability extends beyond simple browser crashes to potentially enable full system compromise when exploited by malicious actors. Attackers can leverage this flaw to execute arbitrary code with the privileges of the browser process, potentially leading to complete system compromise if the browser runs with elevated permissions. The vulnerability affects users who engage with web content that utilizes audio processing features, making it particularly dangerous in environments where users browse untrusted websites or encounter malicious advertisements. Security researchers have noted that this type of compartment mismatch vulnerability is particularly concerning because it can be difficult to detect during normal operation and may not manifest consistently across different system configurations. The affected Firefox versions lack proper memory validation mechanisms that would prevent the compartment mismatch from escalating into exploitable conditions.
Mitigation strategies for this vulnerability require immediate patching of affected Firefox installations to version 65 or later, where the underlying memory management issues have been resolved. Organizations should implement comprehensive browser security policies that enforce automatic updates and restrict access to untrusted web content through content filtering systems. Security teams should monitor for exploitation attempts through network traffic analysis and browser-based monitoring tools that can detect anomalous audio buffer operations. The vulnerability demonstrates the importance of proper memory compartment management in browser security architectures and aligns with common attack patterns documented in the attack technique framework. Additional defensive measures include implementing strict browser sandboxing, using security extensions that monitor for suspicious JavaScript behavior, and conducting regular security assessments of web applications that utilize audio processing APIs. This vulnerability serves as a reminder of the critical need for continuous security testing and validation of browser security features, particularly in areas where JavaScript interacts with system-level resources.