CVE-2015-5747 in Mac OS X
Summary
by MITRE
The fasttrap driver in the kernel in Apple OS X before 10.10.5 allows local users to cause a denial of service (resource consumption) via unspecified vectors.
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Analysis
by VulDB Data Team • 02/03/2025
The fasttrap driver vulnerability identified as CVE-2015-5747 represents a critical resource exhaustion issue within Apple's operating system kernel implementation. This vulnerability affects Apple OS X versions prior to 10.10.5 and specifically targets the fasttrap driver component that facilitates dynamic tracing capabilities in the kernel. The fasttrap driver serves as a mechanism for monitoring system events and providing performance tracing data, making it an integral part of the operating system's diagnostic and monitoring infrastructure. The flaw manifests as an insufficient resource management mechanism that fails to properly validate or limit the consumption of system resources during tracing operations, creating opportunities for malicious exploitation.
The technical nature of this vulnerability stems from inadequate input validation and resource allocation controls within the kernel driver's processing logic. Attackers can exploit this weakness through unspecified vectors that likely involve crafting malicious tracing requests or manipulating the driver's interface to trigger excessive resource consumption patterns. The vulnerability operates at the kernel level, which means that successful exploitation can lead to significant system instability and denial of service conditions. The fasttrap driver's architecture appears to lack proper bounds checking mechanisms that would prevent excessive allocation of kernel memory or other system resources during tracing operations, allowing local users to potentially consume all available resources and render the system unresponsive.
From an operational perspective, this vulnerability poses substantial risks to system availability and stability, particularly in environments where kernel tracing is actively utilized. The resource consumption aspect of this flaw means that local attackers can effectively disrupt system operations without requiring elevated privileges, making it a particularly concerning issue for system administrators and security professionals. The impact extends beyond simple denial of service as the excessive resource consumption can lead to system crashes, application failures, and potentially create conditions that might be exploited for privilege escalation attacks. This vulnerability directly relates to CWE-400, which encompasses resource exhaustion flaws, and aligns with ATT&CK technique T1499.001 for resource exhaustion attacks. The attack surface is broad since the fasttrap driver is part of the standard kernel functionality, making this vulnerability accessible across various system configurations and usage scenarios.
Mitigation strategies for CVE-2015-5747 primarily involve upgrading to Apple OS X 10.10.5 or later versions where the vulnerability has been addressed through proper resource management controls and input validation improvements. System administrators should implement monitoring solutions to detect unusual resource consumption patterns that might indicate exploitation attempts. Additionally, organizations should consider disabling unnecessary kernel tracing capabilities when not actively required for debugging or performance monitoring purposes. The fix implemented by Apple likely involved strengthening the resource allocation logic within the fasttrap driver to enforce proper limits on memory allocation and tracing operations, preventing the accumulation of resources that could lead to system instability. Security teams should also conduct regular vulnerability assessments to identify systems running affected versions and ensure proper patch management procedures are in place to prevent exploitation attempts.