CVE-2015-1236 in Chrome
Summary
by MITRE
The MediaElementAudioSourceNode::process function in modules/webaudio/MediaElementAudioSourceNode.cpp in the Web Audio API implementation in Blink, as used in Google Chrome before 42.0.2311.90, allows remote attackers to bypass the Same Origin Policy and obtain sensitive audio sample values via a crafted web site containing a media element.
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Analysis
by VulDB Data Team • 05/09/2022
The vulnerability identified as CVE-2015-1236 represents a critical security flaw in the Web Audio API implementation within Google Chrome's Blink rendering engine. This issue specifically affects versions prior to 42.0.2311.90 and stems from improper handling of audio data processing within the MediaElementAudioSourceNode component. The flaw enables remote attackers to exploit a bypass of the fundamental Same Origin Policy that normally protects web content from cross-origin data access. The vulnerability occurs during the execution of the MediaElementAudioSourceNode::process function, which is responsible for converting audio data from media elements into audio processing nodes that can be manipulated by JavaScript code.
The technical implementation of this vulnerability exploits the Web Audio API's ability to access and process audio data from media elements, creating a pathway for malicious actors to extract sensitive audio sample values from media content that should be restricted by origin policies. When a malicious website loads a media element and processes it through the Web Audio API, the flawed implementation allows unauthorized access to audio samples that would normally be protected by browser security mechanisms. This represents a significant deviation from expected security boundaries where audio data should remain isolated between different origins, effectively undermining the browser's security model.
The operational impact of this vulnerability extends beyond simple data leakage, as it enables sophisticated attacks that could potentially extract audio fingerprints, voice samples, or other sensitive audio information from media content. Attackers could leverage this flaw to perform cross-origin audio data exfiltration, potentially compromising user privacy when accessing audio content through web applications. The vulnerability particularly affects scenarios where users interact with media elements on untrusted websites, as the malicious code could capture audio samples from media content loaded from different origins, violating fundamental web security principles. This issue demonstrates a critical failure in the sandboxing mechanisms that should prevent unauthorized access to audio resources across different security domains.
Mitigation strategies for CVE-2015-1236 primarily focus on updating affected browser versions to 42.0.2311.90 or later, where the vulnerability has been addressed through proper implementation of Same Origin Policy enforcement. Security researchers and system administrators should also consider implementing additional protective measures such as content security policy headers that restrict audio element access, monitoring for suspicious audio processing activities, and ensuring that users regularly update their browser software. The fix implemented by Google involved strengthening the security boundaries around audio data access within the Web Audio API, ensuring that audio samples from media elements cannot be accessed without proper authorization from the origin that owns the media content. This vulnerability highlights the importance of proper security implementation in web APIs and the critical need for thorough testing of security boundaries in multimedia processing components. The issue aligns with CWE-284, which addresses inadequate access control mechanisms, and represents a clear violation of the principle that web applications should not be able to access resources from other origins without explicit permission, a fundamental concept in the ATT&CK framework's defense evasion techniques.