CVE-2003-1516 in Java Plugin
Summary
by MITRE
The org.apache.xalan.processor.XSLProcessorVersion class in Java Plug-in 1.4.2_01 allows signed and unsigned applets to share variables, which violates the Java security model and could allow remote attackers to read or write data belonging to a signed applet.
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Analysis
by VulDB Data Team • 04/17/2025
The vulnerability described in CVE-2003-1516 represents a critical security flaw in the Java Plug-in 1.4.2_01 implementation that fundamentally undermines the core security principles of the Java sandbox model. This issue affects the org.apache.xalan.processor.XSLProcessorVersion class which is responsible for processing XSLT transformations within the Java environment. The flaw enables a dangerous privilege escalation scenario where both signed and unsigned applets can access and manipulate shared variables, effectively breaking the security boundary that separates trusted code from untrusted code. This vulnerability directly violates the fundamental security model of Java applets by allowing unsigned code to interact with the memory space of signed applets, creating an attack surface that could be exploited by malicious actors.
The technical implementation of this vulnerability stems from improper variable scoping and memory management within the XSLT processing framework. When signed applets execute within the Java Plug-in environment, they typically operate under restricted permissions while unsigned applets are subject to even stricter limitations. However, the flawed XSLProcessorVersion class fails to properly isolate these execution contexts, allowing unsigned applets to access the internal variables and data structures that should remain protected within the signed applet's memory space. This cross-contamination occurs through shared variable references that are not properly secured or validated, creating a pathway for unauthorized data access and modification.
The operational impact of CVE-2003-1516 extends far beyond simple data exposure, as it enables sophisticated attack vectors that could compromise entire application environments. Attackers could potentially read sensitive data from signed applets, including cryptographic keys, user credentials, or confidential business information. The vulnerability also allows for data modification attacks where unsigned code could alter variables within signed applets, potentially corrupting application state or executing unauthorized operations. This flaw particularly affects web applications that rely on signed applets for secure operations, as it essentially nullifies the security benefits that signed code is supposed to provide. The vulnerability is especially dangerous in enterprise environments where signed applets might handle financial transactions, personal data, or other sensitive operations.
This vulnerability maps directly to CWE-254 in the Common Weakness Enumeration catalog, which specifically addresses security weaknesses related to inadequate variable scoping and improper access control. The issue also aligns with several ATT&CK techniques including T1059 for command and script injection, and T1068 for exploit for privilege escalation. Organizations should implement immediate mitigations including updating to patched versions of the Java Plug-in, disabling XSLT processing in untrusted environments, and implementing network segmentation to limit the potential impact of exploitation. Additionally, administrators should review and restrict applet permissions, particularly for XSLT processing components, and consider implementing application whitelisting policies to prevent execution of vulnerable code. The vulnerability highlights the critical importance of maintaining up-to-date security patches and proper code isolation mechanisms in multi-layered security architectures.