CVE-2009-0140 in Mac OS X
Summary
by MITRE
Unspecified vulnerability in the SMB component in Apple Mac OS X 10.4.11 and 10.5.6 allows remote SMB servers to cause a denial of service (memory exhaustion and system shutdown) via a crafted file system name.
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Analysis
by VulDB Data Team • 05/17/2025
The vulnerability identified as CVE-2009-0140 represents a critical flaw within the Server Message Block implementation of Apple Mac OS X versions 10.4.11 and 10.5.6. This issue resides in the SMB component that handles network file sharing protocols, specifically affecting how the operating system processes file system names received from remote SMB servers. The vulnerability operates at the protocol level where the system fails to properly validate or sanitize incoming file system name data, creating a potential attack vector for remote adversaries. The flaw manifests when a malicious SMB server transmits specially crafted file system names that trigger unexpected behavior in the Mac OS X SMB client implementation. This represents a classic example of insufficient input validation, which falls under CWE-20, and demonstrates how improper handling of external data can lead to system instability. The vulnerability operates within the context of network-based attacks where an attacker controls a remote SMB server and can influence the behavior of vulnerable client systems. The impact of this vulnerability extends beyond simple service disruption as it can cause complete system shutdowns, indicating that the memory exhaustion occurs at a fundamental level that affects the operating system's core stability mechanisms. This behavior aligns with the ATT&CK technique T1499.004, which describes denial of service attacks that target system resources. The memory exhaustion aspect suggests that the vulnerable implementation does not properly manage memory allocation when processing the crafted file system names, leading to resource depletion that ultimately causes the system to become unresponsive or shut down entirely. The attack requires minimal privileges as it operates over standard network protocols, making it particularly dangerous in environments where Mac OS X systems interact with untrusted network resources.
The technical exploitation of this vulnerability demonstrates how SMB protocol implementations can be manipulated to cause system instability through seemingly benign data inputs. When a Mac OS X system connects to a malicious SMB server, the client processes the file system name information without adequate safeguards against malformed or excessively large data structures. This processing failure results in memory allocation patterns that consume system resources beyond normal operational limits, eventually leading to system exhaustion and shutdown. The vulnerability specifically targets the SMB client implementation in older Mac OS X versions, indicating that the flaw existed in the protocol handling code that was not properly hardened against adversarial inputs. The crafted file system name likely contains structures or data patterns that cause the system to allocate memory in a way that exhausts available resources, potentially through recursive allocation or improper buffer handling. This memory management issue represents a critical design flaw in the SMB client implementation where the code path for processing file system names does not include proper bounds checking or resource limiting mechanisms. The vulnerability essentially creates a resource exhaustion condition that affects the operating system's ability to maintain normal operations, demonstrating the importance of robust input validation in network protocol implementations. The attack vector is particularly concerning because it can be executed remotely without requiring user interaction, making it suitable for automated exploitation campaigns.
The operational impact of CVE-2009-0140 extends beyond simple service interruption to encompass complete system compromise through denial of service conditions. Organizations running affected Mac OS X versions face significant risk when their systems connect to untrusted SMB servers, as this vulnerability can be exploited to render systems unusable through memory exhaustion attacks. The system shutdown capability indicates that attackers can achieve complete control over system availability, potentially disrupting business operations or creating opportunities for further attacks. This vulnerability particularly affects enterprise environments where Mac systems frequently interact with network resources, including file servers, network shares, and other SMB-enabled services. The impact is amplified in environments where automated processes or network services depend on continuous system availability, as the vulnerability can cause cascading failures throughout network infrastructure. The lack of user interaction requirements makes this vulnerability particularly dangerous for automated exploitation, as attackers can deploy scripts to target multiple systems simultaneously without requiring specific user actions. From a security perspective, this vulnerability demonstrates the critical importance of maintaining up-to-date systems and implementing network segmentation to limit exposure to untrusted SMB servers. The vulnerability's presence in both 10.4.11 and 10.5.6 versions indicates that Apple's SMB implementation had fundamental issues that persisted across multiple releases, highlighting the need for comprehensive security reviews of core protocol implementations. Organizations must consider implementing network monitoring to detect potential exploitation attempts and establish incident response procedures for handling system shutdown events. The vulnerability also underscores the importance of network access controls and the principle of least privilege, as limiting access to potentially malicious SMB servers can significantly reduce the risk of exploitation.
Mitigation strategies for CVE-2009-0140 focus on both immediate protective measures and long-term system hardening approaches. The most effective immediate mitigation involves applying the official security patches provided by Apple, which address the underlying memory handling issues in the SMB client implementation. Organizations should prioritize patch deployment across all affected Mac OS X systems, particularly those that connect to untrusted network resources or SMB servers. Network segmentation represents another critical mitigation approach, where organizations can isolate vulnerable systems from potentially malicious SMB servers through firewall rules and network access controls. Implementing SMB client restrictions that limit automatic connection to remote SMB servers can reduce exposure to this vulnerability. System administrators should also consider disabling SMB services when they are not required, particularly on systems that do not need to connect to SMB servers. The implementation of network monitoring solutions can help detect suspicious SMB traffic patterns that may indicate exploitation attempts, allowing for rapid response to potential attacks. Additionally, organizations should establish robust backup and recovery procedures to ensure business continuity in case of system shutdowns caused by this vulnerability. The vulnerability highlights the importance of maintaining current security patches and implementing comprehensive vulnerability management programs that include regular assessment of protocol implementations. Security awareness training for system administrators can help prevent accidental exposure to malicious SMB servers, while network configuration reviews should ensure that only necessary SMB services are enabled. The mitigation approach should also include regular security assessments of network protocols and implementations to identify similar vulnerabilities that may exist in other system components. Organizations should consider implementing network access controls that restrict SMB traffic to known and trusted sources, reducing the attack surface for this and similar vulnerabilities.