CVE-2015-4475 in Firefox
Summary
by MITRE
The mozilla::AudioSink function in Mozilla Firefox before 40.0 and Firefox ESR 38.x before 38.2 mishandles inconsistent sample formats within MP3 audio data, which allows remote attackers to execute arbitrary code or cause a denial of service (out-of-bounds read) via a malformed file.
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Analysis
by VulDB Data Team • 10/22/2024
The vulnerability identified as CVE-2015-4475 represents a critical security flaw within Mozilla Firefox's audio processing subsystem that affects versions prior to 40.0 and Firefox ESR 38.x prior to 38.2. This issue resides in the mozilla::AudioSink function which is responsible for handling audio data processing within the browser's media framework. The flaw specifically manifests when the function encounters MP3 audio files containing inconsistent sample formats, creating a scenario where the application fails to properly validate or handle the varying data structures present in the audio stream. This vulnerability demonstrates characteristics consistent with a memory safety issue that can be exploited remotely through maliciously crafted media files.
The technical implementation of this vulnerability stems from inadequate bounds checking within the audio sink processing logic. When Firefox encounters an MP3 file with inconsistent sample formats, the mozilla::AudioSink function attempts to process audio data without proper validation of the format consistency, leading to out-of-bounds read conditions. This occurs because the function assumes uniform sample format characteristics throughout the audio stream but fails to account for legitimate variations that may occur in malformed or improperly encoded MP3 files. The flaw operates at the intersection of media parsing and memory management, where insufficient input validation leads to memory access violations that can be leveraged for arbitrary code execution or denial of service attacks.
From an operational perspective, this vulnerability poses significant risks to end users who browse the internet with affected Firefox versions, as it can be triggered through simple web page loading containing maliciously crafted MP3 files. Attackers can exploit this flaw by hosting specially designed audio files on web servers, which when loaded by vulnerable browsers trigger the out-of-bounds read condition. The potential impact includes complete system compromise through arbitrary code execution, making this a high-severity vulnerability that requires immediate attention. The vulnerability aligns with CWE-125 (Out-of-bounds Read) and represents a classic example of how media processing libraries can become attack vectors when proper input validation is absent.
The exploitation of this vulnerability follows patterns consistent with the attack techniques described in the MITRE ATT&CK framework under the Tactic of Execution and Defense Evasion. Remote code execution capabilities make this particularly dangerous in phishing campaigns or compromised websites where attackers can leverage the vulnerability to install malware or gain full system control. Organizations using affected Firefox versions face substantial risk as this vulnerability can be exploited without user interaction beyond visiting a malicious webpage. The issue demonstrates how seemingly benign media processing functionality can become a critical security concern when proper memory safety mechanisms are not implemented.
Mitigation strategies for CVE-2015-4475 primarily involve immediate patching of Firefox installations to versions 40.0 or later for standard releases and 38.2 or later for ESR versions. System administrators should also implement network-level protections such as content filtering to block suspicious audio file types and monitor for unusual network traffic patterns that might indicate exploitation attempts. Browser security enhancements including sandboxing and strict content security policies can provide additional defense-in-depth measures. Organizations should also consider implementing automated patch management systems to ensure rapid deployment of security updates. The vulnerability serves as a reminder of the importance of robust input validation in multimedia processing components and the necessity of thorough security testing for media handling code within web browsers.