CVE-2024-20926: Oracle GraalVM Auth Bypass Vulnerability

CVE-2024-20926 Overview

CVE-2024-20926 is an information disclosure vulnerability affecting the Scripting component of Oracle Java SE, Oracle GraalVM for JDK, and Oracle GraalVM Enterprise Edition. This vulnerability allows an unauthenticated attacker with network access to potentially gain unauthorized access to critical data or complete access to all accessible data within the affected Java environments.

The vulnerability can be exploited through APIs in the Scripting component, including via web services that supply data to these APIs. Additionally, this flaw affects Java deployments running sandboxed Java Web Start applications or sandboxed Java applets that load and execute untrusted code from the internet, potentially bypassing the Java sandbox security model.

Critical Impact

Successful exploitation allows unauthorized access to critical data or complete access to all accessible data in Oracle Java SE, GraalVM for JDK, and GraalVM Enterprise Edition environments.

Affected Products

• Oracle Java SE: 8u391, 8u391-perf, 11.0.21
• Oracle GraalVM for JDK: 17.0.9, 21.0.1
• Oracle GraalVM Enterprise Edition: 20.3.12, 21.3.8, 22.3.4
• Oracle JDK: 1.8.0_update391, 11.0.21, 17.0.9, 21.0.1
• Oracle JRE: 1.8.0_update391, 11.0.21, 17.0.9, 21.0.1
• NetApp Cloud Insights Acquisition Unit
• NetApp Cloud Insights Storage Workload Security Agent
• NetApp OnCommand Insight
• Debian Linux 10.0

Discovery Timeline

• 2024-01-16 - CVE-2024-20926 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2024-20926

Vulnerability Analysis

This vulnerability resides in the Scripting component of Oracle's Java platform products. The Scripting component provides the ability to execute scripts written in languages like JavaScript within the Java Virtual Machine (JVM). The flaw enables attackers to access sensitive data without requiring authentication, though exploitation is considered difficult due to the complexity of the attack conditions required.

The vulnerability is classified under CWE-284 (Improper Access Control), indicating that the underlying issue stems from insufficient access control mechanisms within the Scripting component. When exploited, the vulnerability impacts the confidentiality of data without affecting integrity or availability, meaning attackers can read sensitive information but cannot modify it or cause service disruption.

Root Cause

The root cause of CVE-2024-20926 is an improper access control flaw (CWE-284) within the Scripting component of Oracle Java SE and GraalVM products. The vulnerability allows the Scripting component to improperly handle access permissions when processing scripts, potentially allowing unauthorized data access through specially crafted script execution or API calls.

This type of vulnerability is particularly concerning in environments where Java applications process untrusted input through scripting APIs, as the sandbox security controls that should protect sensitive data can be bypassed.

Attack Vector

The attack vector for CVE-2024-20926 is network-based, requiring no authentication or user interaction. However, the attack complexity is high, meaning specific conditions must be met for successful exploitation:

1. Web Service Exploitation: An attacker can exploit this vulnerability by targeting web services that utilize the Scripting component APIs, sending maliciously crafted data to trigger the information disclosure.

2. Sandboxed Application Exploitation: In client-side scenarios, the vulnerability can be exploited through malicious Java Web Start applications or Java applets that execute untrusted code from the internet. The Java sandbox, which should isolate such code, fails to adequately protect against this attack.

3. API Abuse: Applications that expose Scripting component functionality through APIs may be vulnerable to exploitation when processing attacker-controlled input.

The attack does not require specific privileges or user interaction, making it particularly dangerous for internet-facing Java applications that process external input through scripting mechanisms.

Detection Methods for CVE-2024-20926

Indicators of Compromise

• Unusual script execution requests to Java applications, particularly those involving the Scripting component APIs
• Unexpected data access patterns in Java-based web services that handle script processing
• Log entries showing attempts to access sensitive data through scripting interfaces
• Anomalous network traffic to Java applications on ports commonly used for web services

Detection Strategies

• Monitor Java application logs for unusual Scripting component API invocations from external sources
• Implement network traffic analysis to detect malformed or suspicious script-related requests to Java services
• Deploy application-level monitoring to identify unauthorized data access attempts through scripting APIs
• Use SentinelOne's behavioral AI engine to detect anomalous script execution patterns in Java environments

Monitoring Recommendations

• Enable verbose logging for Java Scripting component activities in production environments
• Configure alerts for high-volume or unusual API calls to scripting endpoints
• Monitor for attempts to load or execute untrusted Java applets or Web Start applications
• Implement network segmentation monitoring to detect lateral movement following potential exploitation

How to Mitigate CVE-2024-20926

Immediate Actions Required

• Update all affected Oracle Java SE installations to the latest patched versions available from Oracle's January 2024 Critical Patch Update
• Upgrade Oracle GraalVM for JDK and GraalVM Enterprise Edition to patched versions
• Audit applications using the Java Scripting component to identify potential exposure points
• Review and restrict network access to Java-based web services that utilize scripting functionality
• Disable Java Web Start and Java applets in environments where they are not required

Patch Information

Oracle has released security patches addressing CVE-2024-20926 as part of the Oracle Critical Patch Update Advisory - January 2024. Organizations should upgrade to the following minimum versions:

• Oracle Java SE: Versions newer than 8u391, 11.0.21, 17.0.9, or 21.0.1
• Oracle GraalVM for JDK: Versions newer than 17.0.9 and 21.0.1
• Oracle GraalVM Enterprise Edition: Versions newer than 20.3.12, 21.3.8, and 22.3.4

Additional vendor-specific guidance is available from NetApp Security Advisory NTAP-20240201-0002 for NetApp products. Debian users should consult the Debian LTS Announcement for package updates.

Workarounds

• Restrict network access to Java applications utilizing the Scripting component to trusted sources only
• Implement Web Application Firewalls (WAF) with rules to filter potentially malicious script-related requests
• Disable the Scripting component in Java applications where it is not essential for functionality
• Block execution of untrusted Java Web Start applications and Java applets through browser and endpoint policies
• Deploy SentinelOne endpoint protection to detect and prevent exploitation attempts in real-time

# Configuration example - Restrict Java Security Manager permissions
# Add to java.policy or application-specific policy file

# Deny script execution from untrusted sources
grant {
    // Remove or restrict permission for scripting operations
    // permission javax.script.ScriptPermission "nashorn.*";
};

# Disable Java Web Start and applets in browser settings
# For Java Plugin Control Panel: Disable "Enable Java content in the browser"