CVE-2008-3637 in Mac OS X
Summary
by MITRE
The Hash-based Message Authentication Code (HMAC) provider in Java on Apple Mac OS X 10.4.11, 10.5.4, and 10.5.5 uses an uninitialized variable, which allows remote attackers to execute arbitrary code via a crafted applet, related to an "error checking issue."
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Analysis
by VulDB Data Team • 08/17/2019
The vulnerability described in CVE-2008-3637 represents a critical security flaw within the Java implementation on Apple Mac OS X systems. This issue specifically affects Java's Hash-based Message Authentication Code (HMAC) provider, which is fundamental to cryptographic operations that ensure data integrity and authentication. The vulnerability manifests in versions 10.4.11, 10.5.4, and 10.5.5 of macOS, where the HMAC implementation contains an uninitialized variable that creates a pathway for malicious exploitation.
The technical root cause of this vulnerability lies in improper memory management within the HMAC cryptographic provider. When processing cryptographic operations, the implementation fails to properly initialize a critical variable before use, creating a scenario where uninitialized memory contents are utilized in subsequent calculations. This uninitialized variable exposure creates a potential code execution vector that remote attackers can leverage through crafted applets. The flaw specifically relates to error checking mechanisms that should validate variable states before cryptographic operations proceed, but instead allow undefined behavior to propagate through the system.
The operational impact of this vulnerability is severe and directly enables remote code execution attacks against affected systems. Attackers can construct malicious Java applets that exploit the uninitialized variable in the HMAC provider to bypass security restrictions and execute arbitrary code with the privileges of the Java runtime environment. This represents a significant escalation from standard sandbox limitations, as the vulnerability allows attackers to move beyond the typical applet security boundaries. The affected Java implementation on macOS systems becomes vulnerable to attacks that could compromise the entire operating system, particularly when users interact with malicious web content or applications.
From a cybersecurity perspective, this vulnerability aligns with CWE-457: Use of Uninitialized Variable, which is a well-documented weakness in software security practices. The attack vector follows patterns consistent with the ATT&CK framework's technique T1059.007 for command and scripting interpreter, where attackers leverage application-level vulnerabilities to execute malicious code. The vulnerability demonstrates the critical importance of proper memory initialization in cryptographic implementations, as uninitialized memory can contain sensitive data or random values that, when used in cryptographic operations, can be manipulated to achieve unintended behavior. Organizations should implement immediate mitigations including system updates, Java runtime restrictions, and network-based protections to prevent exploitation of this vulnerability.
The remediation approach for this vulnerability requires immediate patching of affected macOS versions to address the uninitialized variable issue in the Java HMAC provider. System administrators should also consider implementing Java runtime restrictions, disabling unnecessary applet execution, and monitoring for suspicious network traffic that might indicate exploitation attempts. Security controls should include network segmentation, web application firewalls, and regular vulnerability assessments to ensure that similar memory management issues do not exist in other cryptographic implementations within the environment.