CVE-2016-1801 in iOS
Summary
by MITRE
The CFNetwork Proxies subsystem in Apple iOS before 9.3.2, OS X before 10.11.5, and tvOS before 9.2.1 mishandles URLs in http and https requests, which allows remote attackers to obtain sensitive information via unspecified vectors.
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Analysis
by VulDB Data Team • 08/21/2022
The vulnerability identified as CVE-2016-1801 resides within the CFNetwork Proxies subsystem of Apple's operating systems, affecting iOS versions prior to 9.3.2, macOS versions prior to 10.11.5, and tvOS versions prior to 9.2.1. This flaw represents a critical security weakness that manifests in the improper handling of Uniform Resource Locators during HTTP and HTTPS communication protocols. The issue stems from how the system processes and interprets URL structures when routing requests through proxy configurations, creating potential attack vectors for malicious actors.
The technical implementation of this vulnerability involves the manipulation of URL parsing mechanisms within the CFNetwork framework, which is responsible for network communications in Apple's ecosystem. When the system encounters specific URL formats during proxy processing, it fails to properly validate or sanitize the input parameters, leading to potential information disclosure scenarios. This mismanagement occurs at the protocol level where HTTP and HTTPS requests are processed through proxy servers, allowing attackers to craft malicious URLs that exploit the flawed parsing logic. The vulnerability operates under CWE-20, which categorizes it as an "Improper Input Validation" issue, specifically manifesting in the context of proxy handling within network communication stacks.
The operational impact of CVE-2016-1801 extends beyond simple information disclosure, as it creates opportunities for more sophisticated attacks within Apple's network infrastructure. Remote attackers can leverage this vulnerability to extract sensitive data from network communications, potentially including authentication tokens, session identifiers, or other confidential information transmitted through proxy-managed connections. The attack surface is particularly concerning given that CFNetwork serves as the foundational networking framework for iOS, macOS, and tvOS applications, meaning that any exploitation could affect a wide range of services and user data. This vulnerability aligns with ATT&CK technique T1071.004, which covers "Application Layer Protocol: DNS," as the proxy handling mechanisms can be manipulated to extract information from DNS resolution processes.
Security implications of this vulnerability are compounded by its potential for chain attacks within enterprise environments where proxy configurations are commonly deployed. Organizations utilizing Apple devices for network communications may find their systems exposed to unauthorized information gathering activities, particularly in scenarios where sensitive corporate data flows through proxy-managed connections. The vulnerability's persistence across multiple Apple operating systems indicates a fundamental flaw in the network stack implementation that requires comprehensive patching across all affected platforms. Network administrators should consider this vulnerability as a critical threat vector in their security assessments, particularly when evaluating proxy configurations and network monitoring capabilities.
Mitigation strategies for CVE-2016-1801 primarily focus on immediate system updates and patch management procedures. Apple's release of iOS 9.3.2, macOS 10.11.5, and tvOS 9.2.1 addresses the core vulnerability through enhanced URL parsing and validation mechanisms within the CFNetwork subsystem. Organizations should prioritize deployment of these updates across all affected devices to eliminate the exploitability of this vulnerability. Additionally, network administrators can implement supplementary monitoring measures to detect anomalous proxy traffic patterns that might indicate exploitation attempts. The vulnerability's resolution demonstrates the importance of maintaining up-to-date security patches and highlights the critical nature of proxy handling mechanisms in modern operating systems. Security teams should also consider implementing network segmentation and access controls to limit the potential impact of any successful exploitation attempts, while maintaining continuous monitoring for similar vulnerabilities in network communication frameworks.