CVE-2007-3749 in Mac OS X
Summary
by MITRE
The kernel in Apple Mac OS X 10.4 through 10.4.10 does not reset the current Mach Thread Port or Thread Exception Port when executing a setuid program, which allows local users to execute arbitrary code by creating the port before launching the setuid program, then writing to the address space of the setuid process.
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Analysis
by VulDB Data Team • 07/30/2019
The vulnerability described in CVE-2007-3749 represents a critical security flaw in Apple Mac OS X kernel implementation that persists across versions 10.4 through 10.4.10. This issue stems from improper handling of Mach thread ports during setuid program execution, creating a persistent security risk that can be exploited by local attackers. The flaw specifically involves the kernel's failure to properly reset critical thread port information when transitioning from privileged to unprivileged execution contexts, leaving malicious actors with persistent access vectors within the system's memory space.
The technical root cause of this vulnerability lies in the kernel's inadequate port management during setuid execution flows. When a setuid program is launched, the kernel should properly reset the current Mach Thread Port and Thread Exception Port to prevent unauthorized access to the process's memory space. However, in affected versions, these ports retain their previous values, allowing an attacker who has previously created a malicious thread port to maintain access to the setuid process's address space. This behavior creates a persistent backdoor that can be exploited to execute arbitrary code with elevated privileges, effectively bypassing the intended security boundaries of setuid programs.
The operational impact of this vulnerability is significant as it enables local privilege escalation attacks that can compromise the entire system. Attackers can leverage this flaw by pre-creating a malicious Mach thread port and then executing a setuid program, thereby gaining the ability to write to the target process's memory space. This memory manipulation capability allows for code injection, process hijacking, and complete system compromise. The vulnerability particularly affects system utilities and applications that rely on setuid execution for legitimate administrative functions, making it a potent attack vector that can be exploited across multiple system components.
This vulnerability aligns with CWE-254 and CWE-284 categories, specifically addressing weaknesses in privilege management and improper access control within kernel-level operations. The flaw demonstrates characteristics consistent with the ATT&CK technique T1068, which involves exploiting local privilege escalation opportunities. The persistence of this vulnerability across multiple versions of Mac OS X indicates a fundamental flaw in the kernel's security model that required immediate attention. Organizations should implement immediate mitigations including system updates, monitoring for unauthorized port creation activities, and review of setuid program configurations to prevent exploitation attempts.
The security implications extend beyond immediate code execution to include potential data exfiltration and system persistence mechanisms. Attackers can use this vulnerability to maintain long-term access to compromised systems while remaining undetected by standard security monitoring tools. The vulnerability's exploitation requires local system access but provides elevated privileges that can be used to escalate further attacks, including network reconnaissance and lateral movement within compromised environments. System administrators should prioritize patching affected systems and implement additional security controls to prevent unauthorized creation of Mach thread ports, particularly in environments where multiple users have access to system resources.