CVE-2009-2843 in Mac OS X
Summary
by MITRE
Java for Mac OS X 10.5 before Update 6 and 10.6 before Update 1 accepts expired certificates for applets, which makes it easier for remote attackers to execute arbitrary code via an applet.
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Analysis
by VulDB Data Team • 04/19/2025
The vulnerability identified as CVE-2009-2843 represents a critical security flaw in the Java runtime environment implementation on Mac OS X systems. This issue affects Java versions bundled with Mac OS X 10.5 before Update 6 and 10.6 before Update 1, where the security validation mechanism for digital certificates fails to properly enforce certificate expiration policies. The flaw stems from insufficient certificate validation logic that allows expired certificates to be accepted for applet execution, creating a pathway for malicious actors to bypass security controls that are fundamental to Java's sandboxed execution model.
This vulnerability directly impacts the certificate trust model that Java employs to verify the authenticity and validity of code being executed within the browser or desktop environment. When certificates expire, they are typically rejected by security systems to prevent the execution of potentially compromised or outdated code. However, the flawed implementation in these specific Java versions permits applets signed with expired certificates to run, effectively neutralizing the security boundary that should prevent unauthorized code execution. The technical flaw manifests in the certificate validation routines that fail to properly check certificate validity periods, including expiration dates, during the applet loading process.
The operational impact of this vulnerability is significant as it enables remote attackers to execute arbitrary code on affected systems without requiring user interaction or elevated privileges. Attackers can craft malicious applets signed with expired certificates and deliver them through web pages or other attack vectors, exploiting the trust relationship between the browser and Java runtime. This creates a persistent threat vector where attackers can bypass traditional security controls such as code signing verification, sandbox restrictions, and privilege escalation protections that are normally enforced by the Java security model. The vulnerability essentially undermines the entire code signing infrastructure that Java relies upon to maintain security boundaries.
From a cybersecurity perspective, this vulnerability maps to CWE-295 which describes improper certificate validation, and aligns with several ATT&CK techniques including T1059.007 for command and script interpreter and T1068 for exploit for privilege escalation. The flaw represents a classic case of insufficient validation of security-critical inputs, where the certificate validation process fails to properly enforce security policies. Organizations should implement immediate mitigations including applying the relevant security updates from Apple that address the certificate validation logic, disabling Java applets in web browsers where possible, and implementing network-based controls to monitor for suspicious Java-related traffic. Additionally, system administrators should consider implementing certificate monitoring solutions that can detect and alert on expired certificates being presented for execution, as well as establishing regular patch management processes to ensure timely deployment of security updates across all affected systems.