CVE-2016-4591 in tvOS
Summary
by MITRE
WebKit in Apple iOS before 9.3.3, Safari before 9.1.2, and tvOS before 9.2.2 mishandles the location variable, which allows remote attackers to access the local filesystem via unspecified vectors.
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Analysis
by VulDB Data Team • 09/06/2022
The vulnerability identified as CVE-2016-4591 represents a critical security flaw in Apple's WebKit rendering engine that affected multiple platforms including iOS, Safari, and tvOS. This issue stems from improper handling of the location variable within the WebKit framework, creating a pathway for remote attackers to potentially access local filesystem resources. The vulnerability specifically impacted versions prior to iOS 9.3.3, Safari 9.1.2, and tvOS 9.2.2, indicating a widespread concern across Apple's ecosystem. The flaw falls under the category of information disclosure vulnerabilities, where unauthorized access to sensitive system resources can occur through web-based attacks.
The technical implementation of this vulnerability involves WebKit's mishandling of the location variable, which typically represents the current URL or location within a web page context. When WebKit processes certain JavaScript or HTML elements that interact with the location variable, it fails to properly sanitize or validate inputs, leading to potential information disclosure. This flaw allows attackers to exploit the browser's handling of location-related variables to gain unauthorized access to local filesystem paths and potentially sensitive data stored on the device. The unspecified vectors mentioned in the CVE description suggest that multiple attack surfaces could be leveraged, making the vulnerability particularly concerning from a security perspective.
From an operational standpoint, this vulnerability poses significant risks to users who may unknowingly visit compromised websites or click on malicious links. The remote exploitation capability means that attackers can trigger the vulnerability without requiring physical access to the device, making it a serious concern for enterprise environments and individual users alike. The potential for local filesystem access could enable attackers to read sensitive files, access user data, or even execute additional malicious code on the affected devices. This type of vulnerability directly impacts the principle of least privilege and can lead to complete system compromise depending on the permissions and data available on the compromised device.
Security professionals should consider this vulnerability in relation to CWE-200, which addresses information exposure, and potentially CWE-352, which covers cross-site request forgery conditions that could be exploited in similar contexts. The vulnerability also aligns with ATT&CK techniques related to privilege escalation and information gathering, as attackers can use this flaw to extract sensitive data from the local filesystem. Organizations should prioritize immediate patching of affected systems and implement network monitoring to detect potential exploitation attempts. The remediation strategy should include updating to the patched versions of iOS, Safari, and tvOS, along with implementing additional security measures such as web application firewalls and browser security policies to mitigate potential exploitation vectors.