CVE-2017-14315 in iOS
Summary
by MITRE
In Apple iOS 7 through 9, due to a BlueBorne flaw in the implementation of LEAP (Low Energy Audio Protocol), a large audio command can be sent to a targeted device and lead to a heap overflow with attacker-controlled data. Since the audio commands sent via LEAP are not properly validated, an attacker can use this overflow to gain full control of the device through the relatively high privileges of the Bluetooth stack in iOS. The attack bypasses Bluetooth access control; however, the default "Bluetooth On" value must be present in Settings.
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Analysis
by VulDB Data Team • 01/11/2021
The vulnerability identified as CVE-2017-14315 represents a critical heap overflow flaw within Apple iOS versions 7 through 9, specifically affecting the implementation of the Low Energy Audio Protocol (LEAP) that operates over Bluetooth Low Energy connections. This vulnerability stems from insufficient input validation mechanisms within the Bluetooth stack's audio processing components, creating a pathway for remote code execution through maliciously crafted audio commands. The flaw manifests when the LEAP protocol receives oversized audio command payloads that exceed the allocated heap buffer boundaries, resulting in memory corruption that can be exploited by attackers to execute arbitrary code with elevated privileges. The vulnerability is categorized under CWE-121, heap-based buffer overflow, and aligns with ATT&CK technique T1068, Exploitation for Privilege Escalation, as it leverages the elevated privileges inherent to the Bluetooth stack to achieve system compromise. The attack vector requires no physical proximity or user interaction, as it operates over wireless Bluetooth connections, making it particularly dangerous in public environments where Bluetooth is enabled.
The technical implementation of this vulnerability exploits the fundamental design flaw in how iOS processes LEAP audio commands through the Bluetooth subsystem. When a maliciously crafted audio command is transmitted to a target device, the system fails to properly validate the size and content of the incoming data before processing it within heap memory structures. The LEAP protocol's audio command parsing routine does not implement proper bounds checking or input sanitization, allowing an attacker to send oversized command payloads that overflow the designated memory buffers. This heap overflow creates opportunities for memory corruption that can be leveraged to overwrite critical memory locations including return addresses and function pointers, enabling attackers to redirect execution flow to malicious code. The vulnerability's exploitation potential is amplified by the fact that Bluetooth stack components operate with higher privileges than standard user applications, providing attackers with elevated access levels that can bypass traditional security controls and access system resources directly.
The operational impact of CVE-2017-14315 extends beyond simple remote code execution to encompass complete system compromise and persistent access capabilities. Attackers can leverage this vulnerability to install malicious applications, access sensitive data, monitor user activities, and maintain persistent control over affected devices without requiring user interaction or physical access. The vulnerability's bypass of Bluetooth access controls means that attackers can exploit devices that are simply within wireless range, provided the Bluetooth functionality is enabled in the device settings. This creates a significant risk for users in public spaces, corporate environments, and any location where Bluetooth-enabled devices are present. The default "Bluetooth On" setting requirement means that while the vulnerability is more easily exploitable when Bluetooth is enabled, it can still affect a large number of devices since Bluetooth is often enabled by default on mobile devices. The attack can be executed autonomously without user interaction, making it particularly dangerous as users may not be aware their devices are compromised.
Mitigation strategies for CVE-2017-14315 focus primarily on immediate patch application through Apple's security updates, as the vulnerability was addressed in subsequent iOS releases including iOS 10.0 and later versions. Organizations should implement comprehensive device management policies that enforce automatic security updates and disable Bluetooth when not actively needed. Network administrators should consider implementing Bluetooth access controls and monitoring for unusual Bluetooth activity patterns that may indicate exploitation attempts. The vulnerability's classification as a heap overflow makes it susceptible to various exploitation techniques including return-oriented programming and stack pivoting, which requires defensive measures such as stack canaries, address space layout randomization, and heap integrity checks. Security teams should also monitor for indicators of compromise including unexpected Bluetooth connections, unusual network traffic patterns, and unauthorized application installations. Given the vulnerability's potential for privilege escalation and system compromise, organizations should conduct thorough vulnerability assessments of their mobile device environments and implement network segmentation to limit the potential impact of successful exploitation attempts. The remediation process should also include user education about Bluetooth security settings and the importance of keeping devices updated with the latest security patches to prevent exploitation of this and similar vulnerabilities.