CVE-2011-3215 in Mac OS X
Summary
by MITRE
The kernel in Apple Mac OS X before 10.7.2 does not properly prevent FireWire DMA in the absence of a login, which allows physically proximate attackers to bypass intended access restrictions and discover a password by making a DMA request in the (1) loginwindow, (2) boot, or (3) shutdown state.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 01/19/2025
The vulnerability described in CVE-2011-3215 represents a critical security flaw in Apple Mac OS X operating systems prior to version 10.7.2, specifically targeting the kernel's handling of FireWire Direct Memory Access functionality. This weakness exploits the fundamental design of the FireWire interface and its interaction with system security mechanisms during critical operational states. The vulnerability stems from insufficient protection measures that should have prevented unauthorized DMA operations when the system is in a state where user authentication is required or when the system is transitioning between operational states.
The technical flaw manifests in the kernel's failure to properly enforce access controls for FireWire DMA operations when the system is in loginwindow, boot, or shutdown states. FireWire DMA allows external devices to directly access system memory without CPU intervention, creating a potential attack vector where malicious hardware could bypass normal security boundaries. In the absence of proper authentication, the system fails to prevent DMA requests that could access sensitive memory regions containing password information or authentication tokens. This vulnerability specifically affects systems where the loginwindow is active, during the boot process, or in the shutdown sequence, all of which represent critical states where the system's security posture should be at its strongest.
The operational impact of this vulnerability is severe and exploitable by attackers who have physical proximity to the target system. Attackers can leverage FireWire ports to connect malicious hardware that initiates DMA requests, potentially accessing memory contents that contain user credentials or system authentication data. The attack vector is particularly concerning because it requires minimal sophistication and can be executed with readily available hardware. During loginwindow states, the system's security mechanisms are not fully engaged, making it possible for attackers to read password hashes or other authentication material directly from memory. The vulnerability extends to boot and shutdown states where the system's security controls are temporarily relaxed or not yet fully implemented.
This vulnerability aligns with CWE-284, which addresses improper access control in system components, and represents a failure in privilege management within the kernel's device access controls. The attack pattern corresponds to techniques described in the MITRE ATT&CK framework under T1059 for system compromise and T1068 for local privilege escalation. The vulnerability demonstrates how hardware-level interfaces can be exploited to bypass software-based security controls, particularly when the operating system fails to properly isolate memory regions during critical system states. The attack requires physical access but does not require network connectivity or complex exploitation techniques, making it particularly dangerous in environments where unauthorized physical access is possible.
The recommended mitigations for this vulnerability include updating to Apple Mac OS X 10.7.2 or later versions where the kernel properly enforces FireWire DMA restrictions. System administrators should disable FireWire ports when not actively needed, particularly in high-security environments. Additional protective measures include implementing physical security controls to prevent unauthorized access to systems, configuring automatic screen locking, and ensuring that systems are properly secured during boot and shutdown processes. The fix implemented by Apple addresses the core kernel-level issue by ensuring that FireWire DMA operations are properly restricted during loginwindow, boot, and shutdown states, preventing unauthorized memory access through this hardware interface.