CVE-2018-4278 in Safari
Summary
by MITRE
In Safari before 11.1.2, iTunes before 12.8 for Windows, iOS before 11.4.1, tvOS before 11.4.1, iCloud for Windows before 7.6, sound fetched through audio elements may be exfiltrated cross-origin. This issue was addressed with improved audio taint tracking.
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Analysis
by VulDB Data Team • 04/05/2023
This vulnerability represents a critical cross-origin data exfiltration flaw affecting Apple's ecosystem across multiple platforms including Safari web browser, iTunes, iOS, tvOS, and iCloud for Windows. The vulnerability stems from insufficient taint tracking mechanisms within audio element processing, allowing malicious actors to potentially extract audio data from different origins. The issue specifically impacts versions prior to the security patches released in Safari 11.1.2, iTunes 12.8 for Windows, iOS 11.4.1, tvOS 11.4.1, and iCloud for Windows 7.6. From a technical perspective, this vulnerability enables unauthorized cross-origin information leakage through audio elements, which is particularly concerning given the sensitive nature of audio data that can potentially contain embedded information or metadata.
The technical flaw manifests in the audio element handling subsystem where the browser or application fails to properly track and validate audio data sources. This inadequate taint tracking mechanism allows audio resources fetched from external domains to be processed without proper origin verification, creating a pathway for data exfiltration. The vulnerability is classified under CWE-200, which addresses "Information Exposure," and specifically relates to improper access control in audio processing contexts. The flaw essentially permits malicious websites to access audio content from different origins and potentially extract sensitive information through various audio processing techniques that leverage the browser's audio APIs.
The operational impact of this vulnerability extends beyond simple data leakage, as it represents a significant breach in web browser security boundaries. Attackers could exploit this vulnerability to perform cross-origin audio data extraction, potentially accessing audio streams, sound files, or even audio-based information that might contain embedded data or metadata. This capability undermines the fundamental security principle of origin isolation that web browsers enforce. The vulnerability affects a broad range of Apple products and services, making it particularly dangerous as it could be exploited across multiple attack vectors including web-based attacks, malicious websites, and potentially even through compromised applications.
Mitigation strategies for this vulnerability require immediate patching of affected systems to the latest versions that include improved audio taint tracking mechanisms. Organizations should ensure all Apple products including Safari browsers, iTunes, iOS devices, tvOS systems, and iCloud for Windows are updated to their secure versions. The security improvements implemented in these patches address the root cause by enhancing the taint tracking system to properly validate audio data sources and prevent unauthorized cross-origin access. Additionally, network monitoring should be enhanced to detect unusual audio data access patterns that might indicate exploitation attempts. This vulnerability aligns with ATT&CK technique T1071.004 for application layer protocol: DNS and represents a classic case of insufficient input validation in multimedia processing components. System administrators should also consider implementing additional security controls such as content security policies that restrict audio resource loading from untrusted origins. The fix demonstrates Apple's response to security concerns in web standards compliance and highlights the importance of robust taint tracking in multimedia processing components.