CVE-2008-6252 in smcFanControl
Summary
by MITRE
Stack-based buffer overflow in the smc program in smcFanControl 2.1.2 allows local users to execute arbitrary code and gain privileges via a long -k option.
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Analysis
by VulDB Data Team • 11/11/2024
The vulnerability identified as CVE-2008-6252 represents a critical stack-based buffer overflow flaw within the smc program component of smcFanControl version 2.1.2. This software utility is designed to manage fan control settings on macintosh computers by interfacing with the system management controller. The buffer overflow occurs specifically when processing command-line arguments, particularly the -k option which is intended for kernel-level operations. The flaw stems from inadequate input validation and bounds checking within the argument parsing mechanism, creating an exploitable condition where malicious input can overwrite adjacent memory locations on the stack.
The technical implementation of this vulnerability involves the smc program failing to properly validate the length of the -k command-line argument before copying it into a fixed-size buffer allocated on the stack. When an attacker provides an excessively long argument string, the program continues to write data beyond the allocated buffer boundaries, ultimately overwriting return addresses, saved registers, and other critical stack frame data. This memory corruption directly enables arbitrary code execution with the privileges of the targeted process, which typically runs with elevated permissions due to the kernel-level nature of the smc functionality. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, representing a classic and well-understood exploitation vector that has been documented extensively in cybersecurity literature.
From an operational perspective, this vulnerability poses significant security risks to systems running affected versions of smcFanControl. Local attackers with basic system access can leverage this flaw to escalate their privileges and execute malicious code with system-level privileges, potentially leading to complete system compromise. The attack requires only local access and does not necessitate network connectivity or complex exploitation chains, making it particularly dangerous in environments where local privilege escalation is a concern. The vulnerability affects macOS systems where the smcFanControl utility is installed, and the exploitation process typically involves crafting a specially formatted -k argument that exceeds the buffer capacity while carefully positioning the payload to overwrite the return address and redirect execution flow.
Mitigation strategies for CVE-2008-6252 should focus on immediate patching of the smcFanControl utility to version 2.1.3 or later, which includes proper input validation and bounds checking for command-line arguments. System administrators should also implement privilege separation mechanisms to limit the execution scope of the smc program, ensuring that it runs with minimal necessary permissions. Additional defensive measures include monitoring for unusual command-line argument patterns and implementing application whitelisting policies that restrict execution of unauthorized versions of the smc utility. The vulnerability aligns with ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation' and demonstrates how local privilege escalation can be achieved through buffer overflow exploitation. Organizations should also consider disabling the smcFanControl utility if it is not essential for their operations, as this removes the attack surface entirely. The incident highlights the importance of proper input validation in security-critical applications and underscores the need for regular security updates and vulnerability assessments to prevent exploitation of known flaws in system management utilities.