CVE-2012-4420 in Java SE
Summary
by MITRE
An information disclosure flaw was found in the way the Java Virtual Machine (JVM) implementation of Java SE 7 as provided by OpenJDK 7 incorrectly initialized integer arrays after memory allocation (in certain circumstances they had nonzero elements right after the allocation). A remote attacker could use this flaw to obtain potentially sensitive information.
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Analysis
by VulDB Data Team • 03/17/2024
The vulnerability described in CVE-2012-4420 represents a critical information disclosure flaw within the Java Virtual Machine implementation of Java SE 7 as provided by OpenJDK 7. This issue stems from improper memory initialization practices during the allocation of integer arrays, creating a scenario where certain array elements retain nonzero values immediately following memory allocation rather than being properly initialized to zero. The flaw specifically manifests in circumstances where the JVM fails to adequately clear memory contents before making arrays available to applications, potentially exposing previously stored data that was previously allocated to the same memory locations.
This vulnerability operates at the core memory management level of the JVM, where the improper initialization of integer arrays creates a data leakage condition that can be exploited by remote attackers. The technical implementation flaw occurs during the memory allocation process, where the JVM does not guarantee that newly allocated integer arrays will have all elements initialized to zero, particularly when memory is reused from previous allocations. This behavior violates fundamental security principles of memory isolation and proper initialization, creating potential exposure of sensitive information that may have been previously stored in those memory locations, including cryptographic keys, passwords, or other confidential data.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a persistent security risk that can be leveraged by remote attackers to reconstruct potentially sensitive data. Attackers can exploit this flaw by triggering the allocation of integer arrays in specific patterns that allow them to observe the uninitialized memory contents. The vulnerability affects Java SE 7 implementations provided by OpenJDK 7, making it particularly concerning for widespread deployment across enterprise environments where Java applications are prevalent. The remote exploitation capability means that attackers do not need local access to the system, significantly expanding the attack surface and potential impact.
Security mitigations for this vulnerability should focus on immediate patching of affected OpenJDK 7 implementations to ensure proper memory initialization practices are enforced. System administrators should prioritize updating their Java installations to versions that address this memory allocation behavior and ensure that all Java applications are running on patched versions. Additionally, defensive programming practices should be implemented to minimize reliance on uninitialized memory contents, including explicit initialization of arrays and proper memory management techniques. Organizations should also consider monitoring for suspicious array allocation patterns and implementing memory sanitization techniques to reduce the risk of information leakage. This vulnerability aligns with CWE-1281, which addresses improper initialization in memory management, and represents a significant concern within the ATT&CK framework under the information gathering and credential access phases, as it enables adversaries to obtain sensitive data through memory inspection techniques.