CVE-2011-3227 in Mac OS X
Summary
by MITRE
libsecurity in Apple Mac OS X before 10.7.2 does not properly handle errors during processing of a nonstandard extension in a Certificate Revocation list (CRL), which allows remote attackers to execute arbitrary code or cause a denial of service (application crash) a crafted (1) web site or (2) e-mail message.
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Analysis
by VulDB Data Team • 01/19/2025
The vulnerability identified as CVE-2011-3227 resides within Apple Mac OS X versions prior to 10.7.2, specifically affecting the libsecurity component responsible for certificate handling and validation. This flaw represents a critical security weakness that stems from improper error handling mechanisms when processing Certificate Revocation Lists (CRLs) containing nonstandard extensions. The issue manifests when the system encounters malformed or unexpected CRL extensions during certificate validation processes, creating a potential attack surface for remote adversaries.
The technical implementation of this vulnerability involves the libsecurity framework's insufficient error management during CRL processing operations. When a maliciously crafted CRL containing nonstandard extensions is encountered, the system fails to properly validate or sanitize the extension data before proceeding with certificate validation. This inadequate error handling creates a buffer overflow or memory corruption condition that can be exploited by attackers. The vulnerability specifically targets the certificate validation pipeline where the system attempts to parse and process CRL extensions without proper bounds checking or input sanitization, leading to unpredictable behavior and potential code execution.
The operational impact of this vulnerability extends across multiple attack vectors including web-based and email-based delivery mechanisms. Remote attackers can craft malicious websites or email messages containing specially formatted CRLs designed to trigger the error handling flaw in the libsecurity component. When a user's system processes these malicious CRLs during certificate validation, typically triggered by visiting the compromised website or opening the malicious email, the system crashes or potentially executes arbitrary code. This creates a significant risk for both individual users and enterprise environments where certificate validation occurs automatically during web browsing or email processing activities.
From a cybersecurity perspective, this vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and represents a classic example of improper input validation leading to memory corruption. The attack pattern follows common threat actor methodologies documented in the MITRE ATT&CK framework under techniques related to privilege escalation and code execution through software vulnerabilities. The exploitability of this flaw increases significantly when considering that certificate validation occurs automatically during normal user activities, making user interaction unnecessary for exploitation. Organizations and individuals should prioritize immediate patching to address this vulnerability, as the potential for remote code execution makes it particularly dangerous in enterprise environments where automated certificate validation processes are common.
The remediation strategy for CVE-2011-3227 requires updating to Apple Mac OS X version 10.7.2 or later, which includes corrected error handling mechanisms in the libsecurity component. Security administrators should implement comprehensive patch management procedures to ensure all affected systems receive the necessary updates promptly. Additionally, network administrators may consider implementing certificate validation restrictions or network-level controls to limit exposure while patches are deployed, though the most effective mitigation remains the official software update from Apple.