CVE-2024-10917: Eclipse OpenJ9 JNI Function Vulnerability

CVE-2024-10917 Overview

CVE-2024-10917 is an Integer Overflow vulnerability in Eclipse OpenJ9, a high-performance Java Virtual Machine implementation. In Eclipse OpenJ9 versions up to 0.47, the JNI function GetStringUTFLength may return an incorrect value which has wrapped around due to an integer overflow condition. From version 0.48, the value is correct but may be truncated to include a smaller number of characters.

Critical Impact

Applications relying on accurate string length calculations through JNI may experience data integrity issues, potentially leading to incorrect data processing or security bypasses in string handling operations.

Affected Products

• Eclipse OpenJ9 versions up to and including 0.47
• Applications using JNI GetStringUTFLength function with large strings
• Java applications deployed on vulnerable OpenJ9 runtime environments

Discovery Timeline

• 2024-11-11 - CVE CVE-2024-10917 published to NVD
• 2025-01-09 - Last updated in NVD database

Technical Details for CVE-2024-10917

Vulnerability Analysis

This vulnerability stems from a classic integer overflow condition (CWE-190) in the JNI (Java Native Interface) implementation within Eclipse OpenJ9. The GetStringUTFLength function is designed to return the length in bytes of the modified UTF-8 representation of a Java string. When processing exceptionally large strings, the internal calculation can exceed the maximum value representable by the return type, causing the value to wrap around to a smaller, incorrect number.

The impact manifests as data integrity issues where native code receiving incorrect length values may allocate insufficient buffers, truncate data unexpectedly, or make incorrect processing decisions based on the erroneous length. This vulnerability is exploitable over the network in scenarios where untrusted input can influence string sizes processed through affected JNI calls.

Root Cause

The root cause is an integer overflow in the calculation of UTF-8 byte length within the GetStringUTFLength JNI function. When the actual byte length of a string's UTF-8 representation exceeds the maximum value of the return type, the value wraps around. The fix in version 0.48 addresses the wrap-around issue but introduces a truncation behavior where the returned value may represent fewer characters than actually present in very large strings.

Attack Vector

The vulnerability can be exploited remotely without authentication by providing input that results in extremely large strings being processed through JNI calls. An attacker could craft malicious input designed to trigger the integer overflow, potentially causing:

1. Buffer underallocation in native code relying on the returned length
2. Data truncation or corruption during string processing
3. Bypass of length-based security checks in applications

The attack does not require user interaction and can be executed against any application using the vulnerable GetStringUTFLength function with attacker-controllable string data.

Detection Methods for CVE-2024-10917

Indicators of Compromise

• Unexpected string truncation or data corruption in Java applications using JNI
• Memory corruption indicators in native code interfacing with Java via JNI
• Application crashes or unexpected behavior when processing large string inputs
• Log entries indicating string length mismatches or buffer-related errors

Detection Strategies

• Inventory all systems running Eclipse OpenJ9 and verify version numbers against the vulnerable range (≤0.47)
• Monitor application logs for anomalies in string processing or JNI-related errors
• Implement runtime checks for applications heavily utilizing GetStringUTFLength JNI calls
• Deploy SentinelOne Singularity platform for continuous vulnerability assessment and runtime protection

Monitoring Recommendations

• Enable verbose JNI logging in development and staging environments to identify affected code paths
• Monitor for unusual memory allocation patterns in applications using native Java interfaces
• Track string-related exceptions and errors in application monitoring systems
• Implement alerting for applications processing user-controlled strings through JNI functions

How to Mitigate CVE-2024-10917

Immediate Actions Required

• Upgrade Eclipse OpenJ9 to version 0.48.0 or later immediately
• Identify all applications using JNI string functions that may be affected
• Review application code for reliance on GetStringUTFLength return values for security-critical operations
• Implement input validation to limit maximum string sizes where feasible

Patch Information

Eclipse has addressed this vulnerability in OpenJ9 version 0.48.0. The fix ensures correct value calculation without wrap-around, though very large strings may still experience truncation behavior. Organizations should upgrade to the latest available version through the official OpenJ9 release page. Technical details of the fix can be reviewed in the GitHub Pull Request #20362.

Workarounds

• Implement application-level input validation to reject strings that could trigger the overflow condition
• Add defensive checks in native code that verify string lengths independently before buffer operations
• Consider using alternative JNI string handling methods that may not be affected by this specific issue
• Deploy network-level controls to filter or limit input sizes reaching vulnerable applications