CVE-2016-1858 in Safari
Summary
by MITRE
WebKit, as used in Apple iOS before 9.3.2, Safari before 9.1.1, and tvOS before 9.2.1, improperly tracks taint attributes, which allows remote attackers to obtain sensitive information via a crafted web site.
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Analysis
by VulDB Data Team • 08/21/2022
The vulnerability identified as CVE-2016-1858 represents a critical flaw in WebKit's handling of taint attributes within Apple's mobile and desktop browser ecosystems. This issue affects iOS versions prior to 9.3.2 Safari versions before 9.1.1 and tvOS versions before 9.2.1, creating a significant security risk across multiple Apple platforms. The flaw stems from improper tracking mechanisms that should have prevented unauthorized access to sensitive data through web-based attacks.
WebKit's taint tracking system is designed to monitor and control the flow of potentially sensitive information through the browser's rendering engine. When this system fails to properly track taint attributes, it creates opportunities for attackers to exploit the browser's memory management and data flow controls. The vulnerability specifically targets how the browser handles tainted data - information that has been marked as potentially compromising or sensitive - and fails to maintain proper isolation between different data streams.
The operational impact of this vulnerability is substantial as it allows remote attackers to craft malicious websites that can extract sensitive information from the affected browsers. Attackers can leverage this flaw to potentially access user data, session information, or other confidential details that should remain protected within the browser's security boundaries. This type of information disclosure vulnerability falls under the CWE-200 category of "Information Exposure" and represents a classic case of improper information flow control within a web rendering engine.
The attack vector typically involves a malicious website that manipulates WebKit's taint tracking mechanisms to bypass normal security controls. This allows attackers to access data that should be isolated or protected from unauthorized access. The vulnerability aligns with ATT&CK technique T1056.001 for "Input Injection" and represents a form of data leakage that can be exploited through web-based attack surfaces. The flaw demonstrates how browser security models can be undermined when underlying tracking mechanisms fail to properly enforce data flow policies.
Mitigation strategies for this vulnerability require immediate patching of affected systems to update WebKit components to versions that properly track taint attributes. Organizations should also implement network-level protections such as web application firewalls and content filtering systems to detect and block malicious websites. Browser security configurations should be reviewed to ensure proper sandboxing and data isolation mechanisms are active. Additionally, user education regarding the risks of visiting untrusted websites remains critical in defending against this type of attack vector. The vulnerability highlights the importance of maintaining up-to-date browser security patches and demonstrates how seemingly minor flaws in core browser components can create significant security risks for end users.