CVE-2006-6173 in Mac OS X
Summary
by MITRE
Buffer overflow in the shared_region_make_private_np function in vm/vm_unix.c in Mac OS X 10.4.6 and earlier allows local users to execute arbitrary code via (1) a small range count, which causes insufficient memory allocation, or (2) a large number of ranges in the shared_region_make_private_np_args parameter.
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Analysis
by VulDB Data Team • 06/14/2025
The vulnerability described in CVE-2006-6173 represents a critical buffer overflow flaw within the Mac OS X operating system's memory management subsystem. This issue resides in the shared_region_make_private_np function located in the vm/vm_unix.c file, which is part of the virtual memory implementation responsible for managing shared memory regions. The vulnerability affects Mac OS X versions 10.4.6 and earlier, making it particularly significant as it impacts a widely deployed operating system version during that era. The flaw demonstrates a classic buffer overflow condition where improper input validation leads to memory corruption that can be exploited by local attackers to gain arbitrary code execution privileges.
The technical implementation of this vulnerability stems from inadequate bounds checking within the shared_region_make_private_np function. When processing the shared_region_make_private_np_args parameter, the function fails to properly validate the range count parameter, creating two distinct attack vectors. The first vector involves supplying a small range count value that results in insufficient memory allocation, causing subsequent memory operations to overwrite adjacent memory regions. The second vector exploits large numbers of ranges in the parameter, leading to buffer overflows through excessive memory allocation or manipulation of internal data structures. Both scenarios bypass normal memory safety mechanisms and create opportunities for attackers to manipulate program execution flow through carefully crafted input parameters.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides local attackers with the ability to execute arbitrary code with the privileges of the targeted process. This represents a significant threat vector since local users already have system access and can leverage this vulnerability to gain elevated privileges or compromise system integrity. The vulnerability operates at the kernel level within the virtual memory subsystem, making exploitation particularly dangerous as it can potentially lead to complete system compromise. Attackers can manipulate shared memory regions to overwrite critical kernel data structures or inject malicious code into memory spaces, effectively undermining the operating system's security model and memory protection mechanisms.
From a cybersecurity perspective, this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a prime example of improper input validation leading to memory corruption. The ATT&CK framework categorizes this as a privilege escalation technique through kernel exploitation, where attackers leverage system-level vulnerabilities to gain elevated system privileges. The vulnerability's exploitation requires local access but provides a pathway to system compromise, making it particularly concerning for enterprise environments where local user accounts may be accessible to unauthorized individuals. Security professionals should note that this vulnerability demonstrates the importance of rigorous input validation and bounds checking in kernel-level code, as even seemingly benign parameters can lead to catastrophic security failures when not properly validated.
Mitigation strategies for this vulnerability involve immediate system updates to patched versions of Mac OS X, as Apple would have released security updates addressing the specific buffer overflow conditions. System administrators should implement comprehensive patch management processes to ensure all affected systems receive timely updates. Additional defensive measures include monitoring for unusual memory allocation patterns and implementing runtime protection mechanisms that can detect and prevent buffer overflow exploitation attempts. The vulnerability highlights the necessity of maintaining up-to-date security patches and the importance of security audits focusing on kernel-level code validation to prevent similar issues in future software deployments.