CVE-2015-7035 in Mac OS X
Summary
by MITRE
Apple Mac EFI before 2015-002, as used in OS X before 10.11.1 and other products, mishandles arguments, which allows attackers to reach "unused" functions via unspecified vectors.
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Analysis
by VulDB Data Team • 11/19/2024
The vulnerability identified as CVE-2015-7035 represents a critical flaw in Apple's Extensible Firmware Interface implementation within Mac computers prior to the 2015-002 update. This issue specifically affects the firmware layer that governs the initial system boot process and hardware initialization sequence. The vulnerability stems from improper argument handling within the EFI firmware code, creating a pathway for malicious actors to execute unintended code sequences. The flaw exists in the EFI runtime services where function calls are processed without adequate validation of input parameters, allowing attackers to manipulate the execution flow through carefully crafted arguments that lead to previously unused or untested code paths.
The technical exploitation of this vulnerability occurs through manipulation of EFI firmware arguments during the boot process, which can be achieved through various attack vectors including malicious USB devices, network-based firmware updates, or compromised boot media. This type of vulnerability falls under the CWE-254 category of "Security Features," specifically addressing weaknesses in the implementation of access control mechanisms. The flaw essentially creates a bypass scenario where attackers can leverage the firmware's argument parsing logic to jump to arbitrary code locations within the EFI environment, potentially enabling privilege escalation and persistent system compromise. The unspecified vectors mentioned in the description suggest that multiple attack surfaces may be exploitable, including but not limited to firmware update mechanisms, boot loader interfaces, and hardware initialization routines.
The operational impact of CVE-2015-7035 extends beyond simple code execution as it provides attackers with a foothold at the lowest level of system security. Since EFI firmware operates with the highest privilege level and has direct access to hardware components, successful exploitation could enable attackers to establish persistent backdoors, modify system integrity checks, or even create rootkits that persist across operating system reinstallation. This vulnerability is particularly concerning because it operates below the operating system level, making traditional security controls ineffective. The attack surface encompasses not only the immediate system compromise but also potential lateral movement within networks where infected systems could serve as launching points for broader attacks. The vulnerability's persistence across multiple Apple products and operating system versions increases its potential impact, as it affects a wide range of hardware configurations and software environments.
Mitigation strategies for CVE-2015-7035 primarily focus on applying the official firmware updates released by Apple, specifically the 2015-002 EFI update that addressed the argument handling flaws. Organizations should implement comprehensive firmware update policies that ensure all Mac systems receive the latest security patches, particularly those that address EFI-level vulnerabilities. Network administrators should monitor for unauthorized firmware modifications and implement hardware security measures such as Trusted Platform Module (TPM) integration where available. The remediation process requires careful consideration of the update procedure to avoid potential boot failures, as firmware updates at this level can be critical to system stability. Additionally, security teams should conduct regular vulnerability assessments focusing on firmware components and implement monitoring solutions that can detect unauthorized changes to EFI variables or boot processes. This vulnerability aligns with ATT&CK technique T1068 which covers "Exploitation for Privilege Escalation" and demonstrates how low-level firmware vulnerabilities can be leveraged to achieve system-level compromise.