CVE-2009-2829 in Mac OS X
Summary
by MITRE
Event Monitor in Apple Mac OS X 10.5.8 does not properly handle crafted authentication data sent to an SSH daemon, which allows remote attackers to cause a denial of service via vectors involving processing of XML log documents by other services, related to a "log injection" issue.
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Analysis
by VulDB Data Team • 06/02/2025
The vulnerability identified as CVE-2009-2829 resides within the Event Monitor component of Apple Mac OS X 10.5.8, specifically manifesting in how the system handles authentication data when processed by the SSH daemon. This flaw represents a classic example of improper input validation that enables malicious actors to manipulate system behavior through crafted data payloads. The vulnerability stems from insufficient sanitization of authentication data during SSH session establishment, creating an opportunity for attackers to inject malicious content that affects downstream processing within the system's logging infrastructure.
The technical mechanism behind this vulnerability involves XML log document processing where crafted authentication data can contain malicious payloads that, when processed by other system services, trigger unexpected behavior. This log injection issue occurs because the Event Monitor fails to properly validate or sanitize the XML content generated during SSH authentication processes. The vulnerability specifically impacts the XML parsing routines that handle log data, allowing attackers to inject malformed XML structures that disrupt normal system operations. The flaw demonstrates a weakness in the principle of least privilege and input validation, where the system assumes all incoming authentication data is trustworthy without proper sanitization checks.
Operationally, this vulnerability creates a significant denial of service condition that can compromise the availability of system services. Remote attackers can exploit this weakness to cause system instability by injecting specially crafted XML content that affects the Event Monitor's processing capabilities. The impact extends beyond simple service disruption as the vulnerability affects multiple system components that rely on XML log processing, potentially creating cascading failures across various services. The attack vector is particularly concerning because it requires no local access or authentication, making it a remotely exploitable vulnerability that can be leveraged by any attacker with network access to the affected system.
The security implications of CVE-2009-2829 align with CWE-20, which describes improper input validation, and reflects the broader category of injection flaws that have been consistently identified as critical vulnerabilities in system security. This vulnerability also maps to ATT&CK technique T1059.007 for command and scripting interpreter, as the injection occurs through XML processing that can potentially execute unintended system commands. The weakness demonstrates poor separation of concerns in system design where authentication handling directly influences logging infrastructure without proper boundary checking. Organizations should implement immediate mitigations including system updates, network segmentation, and monitoring for anomalous XML log entries to prevent exploitation of this vulnerability.
Mitigation strategies should focus on patch management with the latest security updates from Apple, along with network-level controls that monitor and filter XML content passing through SSH services. The implementation of proper input validation mechanisms and XML schema validation can help prevent similar injection attacks. Additionally, system administrators should establish robust monitoring protocols to detect unusual patterns in log processing that might indicate exploitation attempts. The vulnerability underscores the importance of maintaining up-to-date system configurations and implementing defense-in-depth strategies that protect against multiple attack vectors simultaneously. Organizations should also consider implementing intrusion detection systems that can identify and alert on suspicious XML injection patterns within their network infrastructure.