CVE-2015-5746 in iOS
Summary
by MITRE
AppleFileConduit in Apple iOS before 8.4.1 allows attackers to bypass intended restrictions on filesystem access via an afc command that leverages symlink mishandling.
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Analysis
by VulDB Data Team • 10/14/2017
The vulnerability identified as CVE-2015-5746 resides within AppleFileConduit, a component of Apple iOS operating systems prior to version 8.4.1. This flaw represents a critical security weakness that undermines the intended filesystem access controls and privilege separation mechanisms that protect iOS devices from unauthorized data access and manipulation. The vulnerability specifically targets the handling of symbolic links within the afc command interface, creating a pathway for malicious actors to circumvent security boundaries that should otherwise restrict filesystem operations to authorized applications and users.
The technical exploitation of this vulnerability stems from improper handling of symbolic link resolution within the AppleFileConduit service. When processing afc commands, the system fails to adequately validate or sanitize symbolic link references, allowing attackers to craft malicious command sequences that traverse filesystem boundaries beyond their intended scope. This mishandling creates a privilege escalation vector where unauthorized access to protected directories, files, and system resources becomes possible through carefully constructed symlink manipulation. The flaw operates at the core of iOS's file access control mechanisms, fundamentally compromising the sandboxing principles that isolate applications from each other and from system-level resources.
The operational impact of CVE-2015-5746 extends beyond simple unauthorized file access, as it enables attackers to potentially escalate privileges and gain deeper system control. An attacker exploiting this vulnerability could access sensitive user data, system configuration files, and application resources that should remain protected. The implications are particularly severe given that AppleFileConduit operates with elevated privileges necessary for device management functions, making successful exploitation a significant threat to device integrity and user privacy. This vulnerability essentially provides a backdoor mechanism that bypasses the normal security model enforcement, allowing for arbitrary filesystem traversal and data access that could lead to complete device compromise.
Security professionals should note this vulnerability aligns with CWE-59 and CWE-22 categories, specifically addressing improper link resolution and path traversal issues that have been consistently identified as critical flaws in operating system security models. The attack pattern associated with CVE-2015-5746 corresponds to techniques documented in the MITRE ATT&CK framework under privilege escalation and defense evasion tactics, where adversaries leverage system-level components to bypass security controls. Organizations and users should prioritize immediate patching to iOS version 8.4.1 or later, as this vulnerability represents a persistent threat that could be exploited by adversaries with minimal technical expertise. The recommended mitigation strategy involves implementing comprehensive mobile device management policies that ensure timely security updates and monitoring for unauthorized access attempts. Additionally, system administrators should consider network-based detection measures to identify potential exploitation attempts and maintain detailed audit logs of filesystem access patterns to detect anomalous behavior indicative of symlink-based attacks.