CVE-2015-7079 in iOS
Summary
by MITRE
dyld in Apple iOS before 9.2 and tvOS before 9.1 mishandles segment validation, which allows attackers to execute arbitrary code in a privileged context via a crafted app.
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Analysis
by VulDB Data Team • 06/29/2022
The vulnerability identified as CVE-2015-7079 resides within the dynamic link editor dyld component of Apple's iOS and tvOS operating systems. This flaw represents a critical security weakness that affects versions prior to iOS 9.2 and tvOS 9.1, where the system's segment validation mechanism fails to properly verify the integrity of executable code segments within applications. The issue stems from insufficient validation routines that should normally ensure code segments are properly aligned and do not contain malicious payloads designed to bypass system security measures.
The technical exploitation of this vulnerability occurs through a crafted malicious application that manipulates the segment validation process within dyld. When iOS or tvOS attempts to load and execute such an application, the flawed validation logic allows unauthorized code segments to be loaded into memory without proper verification. This privilege escalation vulnerability enables attackers to execute arbitrary code with elevated privileges typically reserved for system-level processes, effectively bypassing the normal security boundaries that separate user applications from system components. The flaw operates at the kernel level where dyld interacts with memory management and code execution mechanisms, making it particularly dangerous as it can be leveraged to gain root access to the device.
The operational impact of CVE-2015-7079 extends beyond simple code execution, as it fundamentally undermines the security model of Apple's mobile operating systems. Attackers can leverage this vulnerability to install malicious software, access sensitive user data, modify system files, or even create persistent backdoors on compromised devices. The vulnerability's exploitation requires only a single malicious application, making it highly effective for widespread attacks. This weakness affects the core security architecture of iOS and tvOS, potentially enabling attackers to circumvent sandboxing mechanisms, code signing requirements, and other critical security controls that normally protect mobile devices from unauthorized access and malicious code execution.
Security researchers have classified this vulnerability under CWE-264, which deals with Permissions, Privileges, and Access Controls, specifically highlighting the improper handling of privilege levels during code loading operations. The attack pattern aligns with techniques described in the ATT&CK framework under T1059 for command and scripting interpreter and T1068 for exploit for privilege escalation, demonstrating how an initial compromise can lead to system-level control. Organizations and users affected by this vulnerability should immediately implement patch management procedures to upgrade to iOS 9.2 or tvOS 9.1, which contain the necessary fixes to properly validate memory segments during the dynamic linking process. Additional mitigations include implementing mobile device management solutions that can detect and prevent the installation of untrusted applications, along with monitoring for suspicious application behavior that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of proper memory management and validation routines in operating system components, particularly those that handle code loading and execution in privileged contexts.