CVE-2015-3726 in iOS
Summary
by MITRE
The Telephony subsystem in Apple iOS before 8.4 allows physically proximate attackers to execute arbitrary code via a crafted (1) SIM or (2) UIM card.
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Analysis
by VulDB Data Team • 07/02/2017
The vulnerability identified as CVE-2015-3726 represents a critical security flaw within Apple iOS operating systems prior to version 8.4, specifically affecting the Telephony subsystem. This weakness enables attackers who are physically present near a targeted device to potentially execute malicious code through the manipulation of SIM or UIM cards. The vulnerability exploits the trust relationship between the mobile device and the cellular network components, creating an attack surface that leverages hardware-level interactions rather than traditional software-based exploits.
The technical implementation of this vulnerability stems from insufficient validation mechanisms within the telephony stack when processing data from SIM and UIM cards. These cards contain essential information for network authentication and device identification, including integrated circuit card identifiers and cryptographic keys. The flaw allows an attacker to craft specially designed SIM or UIM cards that contain malicious data structures or manipulated authentication parameters. When the iOS device reads these cards during normal operation, the malformed data triggers unexpected behavior in the telephony subsystem, potentially leading to privilege escalation and arbitrary code execution. This type of vulnerability falls under the CWE-119 weakness category, which encompasses memory safety issues and improper input validation, specifically related to buffer overflows and data processing errors.
The operational impact of CVE-2015-3726 is particularly concerning due to its proximity requirement and execution capabilities. Attackers need only physical access to the target device to deploy this exploit, making it a significant threat in environments where devices might be left unattended or where social engineering attacks could be employed to gain access. The arbitrary code execution capability allows threat actors to install malware, access sensitive data, modify device functionality, or potentially escalate privileges to gain full system control. This vulnerability directly maps to several ATT&CK techniques including privilege escalation through hardware manipulation and initial access via physical proximity attacks. The attack vector specifically aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation, as the vulnerability enables execution of malicious code with elevated privileges.
Mitigation strategies for this vulnerability require both immediate and long-term approaches to address the underlying security gaps. Users should immediately update to iOS version 8.4 or later, which contains patches specifically addressing the telephony subsystem validation issues. Organizations implementing mobile device management solutions should ensure all iOS devices within their environment are updated and monitored for compliance. Network administrators should consider implementing additional security measures such as device enrollment in MDM solutions that can enforce security policies and provide real-time monitoring capabilities. The vulnerability also highlights the importance of supply chain security and the need for hardware vendors to implement proper validation mechanisms for SIM and UIM card data processing. Security professionals should also consider implementing physical security controls to prevent unauthorized access to mobile devices and establish incident response procedures for potential exploitation attempts. This vulnerability demonstrates the critical importance of hardware-level security validation and the potential for physical attack vectors to compromise mobile device security, reinforcing the need for comprehensive security approaches that consider both software and hardware attack surfaces.