CVE-2020-2805 Overview
CVE-2020-2805 is a sandbox bypass vulnerability in the Java SE and Java SE Embedded products of Oracle Java SE, specifically affecting the Libraries component. This vulnerability allows an unauthenticated attacker with network access to potentially achieve complete takeover of affected Java deployments through the execution of malicious code that escapes the Java sandbox.
The vulnerability is particularly concerning for environments running sandboxed Java Web Start applications or Java applets that load and execute untrusted code from the internet. Successful exploitation requires user interaction and is difficult to execute, but the potential impact extends beyond the vulnerable component itself, potentially affecting additional products in the environment.
Critical Impact
Successful exploitation can result in complete takeover of Java SE and Java SE Embedded, with high impacts to confidentiality, integrity, and availability. The scope change indicates attacks may significantly impact additional products beyond the vulnerable Java component.
Affected Products
- Oracle JDK 7u251, 8u241, 11.0.6, and 14
- Oracle JRE 7u251, 8u241, 11.0.6, and 14
- Oracle OpenJDK (multiple versions through 7u251, 8u241, and 14)
- Java SE Embedded 8u241
- NetApp products including Active IQ Unified Manager, Cloud Backup, E-Series SANtricity, OnCommand Insight, and StorageGRID
- Debian Linux 8.0, 9.0, and 10.0
- Fedora 30, 31, and 32
- openSUSE Leap 15.1 and 15.2
- Ubuntu Linux 16.04, 18.04, and 19.10
Discovery Timeline
- April 15, 2020 - CVE-2020-2805 published to NVD
- November 21, 2024 - Last updated in NVD database
Technical Details for CVE-2020-2805
Vulnerability Analysis
This vulnerability resides in the Libraries component of Oracle Java SE and Java SE Embedded. The flaw enables an unauthenticated attacker to bypass the Java sandbox security model, which is designed to prevent untrusted code from performing dangerous operations on the host system.
The vulnerability primarily affects client-side Java deployments where sandboxed Java Web Start applications or Java applets execute untrusted code retrieved from the internet. In these scenarios, the Java sandbox serves as the primary security boundary between untrusted code and system resources. A successful bypass allows malicious code to escape these restrictions and execute with elevated privileges.
Server-side Java deployments that only load and run trusted code (such as administrator-installed applications) are not affected by this vulnerability, as they do not rely on the sandbox for security isolation.
Root Cause
The root cause stems from insufficient security checks within the Java Libraries component that fail to properly enforce sandbox restrictions under certain conditions. This allows specially crafted code to bypass the security boundaries that would normally prevent untrusted applets and Web Start applications from accessing protected system resources.
The vulnerability classification as "NVD-CWE-noinfo" indicates that specific details about the underlying weakness have not been publicly disclosed, which is common for Oracle Java vulnerabilities to prevent exploitation before patches are widely deployed.
Attack Vector
An attacker exploits this vulnerability by crafting a malicious Java applet or Web Start application and convincing a user to execute it. The attack requires:
- Network access to deliver the malicious payload via HTTP/HTTPS
- User interaction to trigger execution of the malicious Java code
- A vulnerable Java runtime on the client system configured to run applets or Web Start applications
The attack complexity is high because specific conditions must be met for successful exploitation. However, the impact is severe as successful attacks can achieve complete system compromise with the ability to read, modify, or delete data, and potentially pivot to attack other systems.
The vulnerability is particularly dangerous because attacks may significantly impact additional products beyond the Java runtime itself, as indicated by the scope change characteristic.
Detection Methods for CVE-2020-2805
Indicators of Compromise
- Unexpected Java processes spawning child processes or making network connections
- Java applet or Web Start execution from untrusted sources followed by suspicious system activity
- Abnormal file system access patterns originating from Java processes
- Network connections to unknown external hosts initiated by Java runtime processes
Detection Strategies
- Monitor for execution of Java Web Start (javaws) and applet-related processes from browser contexts
- Implement endpoint detection rules for Java processes accessing sensitive system directories or registry keys
- Deploy network monitoring for suspicious outbound connections from Java runtime processes
- Enable Java deployment rule sets to restrict applet execution to trusted sources only
Monitoring Recommendations
- Enable Java console and trace logging to capture detailed runtime behavior
- Configure SentinelOne endpoint agents to monitor Java process behaviors for sandbox escape indicators
- Review Java deployment configurations to ensure security prompts are enabled for unsigned applications
- Implement web proxy logging to track Java Network Launch Protocol (JNLP) file downloads
How to Mitigate CVE-2020-2805
Immediate Actions Required
- Update to the patched Java versions released in Oracle's April 2020 Critical Patch Update immediately
- Disable Java applet support in web browsers where not required for business operations
- Restrict Java Web Start execution to signed applications from trusted publishers only
- Implement Java deployment rule sets to block execution of untrusted Java content
Patch Information
Oracle addressed this vulnerability in the April 2020 Critical Patch Update. Organizations should upgrade to the following minimum versions:
- Java SE 7u261 or later
- Java SE 8u251 or later
- Java SE 11.0.7 or later
- Java SE 14.0.1 or later
Patches are available from the Oracle Critical Patch Update April 2020 advisory page. Linux distributions have also released security updates: see Debian Security Advisory DSA-4662, Ubuntu Security Notice USN-4337-1, and Gentoo GLSA 202006-22 for distribution-specific updates.
Workarounds
- Disable Java plugin in all web browsers to prevent applet execution entirely
- Configure Java security settings to require user approval before running any unsigned applications
- Remove Java Web Start if not required for business applications
- Implement network-level blocking of JNLP file downloads from untrusted sources
- Use application control policies to restrict which users and applications can invoke Java runtime
# Disable Java plugin in browser deployments via deployment.properties
echo "deployment.webjava.enabled=false" >> /etc/.java/deployment/deployment.properties
echo "deployment.javaws.enabled=false" >> /etc/.java/deployment/deployment.properties
echo "deployment.security.level=VERY_HIGH" >> /etc/.java/deployment/deployment.properties
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
