CVE-2011-0185 in Mac OS X
Summary
by MITRE
Format string vulnerability in the debug-logging feature in Application Firewall in Apple Mac OS X before 10.7.2 allows local users to gain privileges via a crafted name of an executable file.
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Analysis
by VulDB Data Team • 11/23/2021
The vulnerability identified as CVE-2011-0185 represents a critical format string flaw within the Application Firewall component of Apple Mac OS X operating systems. This security weakness specifically affects versions prior to 10.7.2 and resides within the debug-logging functionality of the firewall system. The flaw manifests when the system processes executable file names through a vulnerable logging mechanism that does not properly sanitize user input before formatting output strings. This particular vulnerability falls under the CWE-134 category of format string vulnerability, where attacker-controlled data is passed directly to formatting functions without proper validation or escaping.
The technical exploitation of this vulnerability occurs when a local attacker crafts a specially formatted executable file name that contains format specifiers such as %s, %x, or %n. When the Application Firewall's debug logging feature encounters this crafted filename during normal system operations, the improper string formatting causes the logging function to interpret these specifiers as instructions for memory access or execution. This misbehavior can lead to arbitrary code execution within the context of the firewall process, which typically runs with elevated privileges due to its system-level nature. The vulnerability's impact is amplified by the fact that it operates within the kernel-level firewall subsystem, making successful exploitation potentially devastating for system integrity.
From an operational perspective, this vulnerability creates a significant risk for local attackers who can leverage it to escalate privileges from standard user accounts to system-level access. The attack vector is particularly concerning because it requires only local system access, making it accessible through various means including social engineering, physical access, or exploitation of other initial compromise vectors. The debug logging feature, while intended for system administrators and developers to diagnose issues, becomes a dangerous attack surface when it fails to properly validate input parameters. This vulnerability aligns with ATT&CK technique T1068 which describes the use of local privilege escalation techniques, and specifically targets the privilege escalation sub-technique T1068.003 related to security software bypass.
The mitigation strategies for CVE-2011-0185 primarily involve updating to Apple Mac OS X 10.7.2 or later versions where the vulnerability has been patched. Apple addressed this issue by implementing proper input validation and sanitization within the debug logging functions, ensuring that user-supplied data cannot be interpreted as format specifiers. System administrators should also consider implementing additional security controls such as restricting local user access to system files and monitoring for unusual logging activity that might indicate exploitation attempts. The fix demonstrates proper defensive programming practices that align with secure coding guidelines and represents a classic example of how format string vulnerabilities can be prevented through careful input validation and parameterized string operations. Organizations should also conduct regular vulnerability assessments to identify similar issues in other applications and system components that might be susceptible to the same class of vulnerabilities.