CVE-2020-14803: Oracle OpenJDK Information Disclosure Flaw

CVE-2020-14803 Overview

CVE-2020-14803 is an information disclosure vulnerability affecting the Libraries component of Oracle Java SE. This easily exploitable flaw allows unauthenticated attackers with network access to gain unauthorized read access to a subset of Java SE accessible data via multiple protocols. The vulnerability primarily impacts Java deployments in client environments running sandboxed Java Web Start applications or sandboxed Java applets that load and run untrusted code from the internet and rely on the Java sandbox for security.

Critical Impact

Unauthenticated attackers can remotely access sensitive data through client-side Java applications running untrusted code, bypassing sandbox protections intended to isolate untrusted content.

Affected Products

• Oracle Java SE 11.0.8 and 15
• Oracle OpenJDK versions 7, 8, 11, 13, and 15 (multiple updates)
• Oracle GraalVM Enterprise 19.3.3, 19.3.4, 20.2.0, and 20.3.0
• Oracle JDK 1.7.0_281, 1.8.0_271, 11.0.8, and 15.0
• Oracle JRE 1.7.0_281, 1.8.0_271, 11.0.8, and 15.0
• NetApp Active IQ Unified Manager, OnCommand Insight, and related products
• Debian Linux 9.0 and 10.0
• openSUSE Leap 15.2

Discovery Timeline

• October 21, 2020 - CVE-2020-14803 published to NVD
• May 27, 2025 - Last updated in NVD database

Technical Details for CVE-2020-14803

Vulnerability Analysis

This vulnerability resides in the Libraries component of Oracle Java SE and affects the security sandbox mechanism that is designed to isolate untrusted code execution. The flaw enables unauthorized information disclosure, allowing attackers to read data that should be protected by the Java security model. The vulnerability is particularly concerning for client-side deployments where Java Web Start applications or Java applets process untrusted code from external sources.

The attack does not require any privileges or user interaction, making it straightforward to exploit in vulnerable environments. However, the impact is limited to confidentiality breaches affecting a subset of accessible data, with no direct impact on data integrity or system availability. Server-side Java deployments that only run trusted, administrator-installed code are not affected by this vulnerability.

Root Cause

The root cause stems from improper access controls or information handling within the Java SE Libraries component. The vulnerability allows the Java sandbox to be bypassed in specific scenarios where untrusted code can access data that should be restricted. This represents a failure in the security boundary enforcement that the sandbox is designed to provide for client-side Java applications processing untrusted content.

Attack Vector

An attacker can exploit this vulnerability by crafting malicious Java Web Start applications or Java applets designed to be executed in a sandboxed environment. When a victim loads and runs this untrusted code, the attacker can leverage the flaw to read sensitive information that should be protected by the sandbox. The attack can be delivered via multiple network protocols, increasing the potential attack surface.

The exploitation scenario involves:

1. Attacker creates a malicious Java applet or Web Start application containing exploit code
2. Victim accesses and runs the untrusted application in a sandboxed Java environment
3. The exploit bypasses sandbox restrictions to access protected data
4. Sensitive information is disclosed to the attacker

Detection Methods for CVE-2020-14803

Indicators of Compromise

• Unusual network traffic patterns from Java applications attempting to access restricted resources
• Java processes accessing files or data outside expected sandbox boundaries
• Anomalous behavior in Java Web Start or applet execution environments
• Unexpected outbound connections from sandboxed Java applications

Detection Strategies

• Monitor Java runtime environments for execution of untrusted applets or Web Start applications from unknown sources
• Implement application whitelisting to control which Java applications can execute in your environment
• Deploy network monitoring to detect data exfiltration attempts from Java processes
• Enable Java security logging to capture sandbox violation attempts and security exceptions

Monitoring Recommendations

• Configure Java runtime to log security-related events and sandbox access attempts
• Monitor endpoint detection systems for suspicious Java process behavior indicative of sandbox escape
• Implement SIEM rules to correlate Java application activity with potential data access violations
• Review web proxy logs for requests to untrusted Java content sources

How to Mitigate CVE-2020-14803

Immediate Actions Required

• Update all Oracle Java SE, OpenJDK, and GraalVM installations to the latest patched versions
• Review and restrict the use of Java Web Start applications and applets in your environment
• Disable Java browser plugins if not required for business operations
• Audit systems for vulnerable Java versions using automated vulnerability scanning

Patch Information

Oracle addressed this vulnerability in the October 2020 Critical Patch Update. Organizations should apply the patches available through the Oracle Critical Patch Update October 2020. Additional fixes were included in the Oracle Critical Patch Update January 2021.

For Linux distributions, security updates are available:

• Debian users should apply updates per DSA-4779 and the Debian LTS Security Notice
• openSUSE users should reference the openSUSE Security Announcement
• Gentoo users should apply GLSA 2021-01-19
• NetApp product users should consult the NetApp Security Advisory

Workarounds

• Disable Java Web Start and browser-based Java applet execution if not required for business functions
• Configure strict security settings in the Java Control Panel to block untrusted code execution
• Implement network-level controls to prevent access to untrusted Java content sources
• Consider migrating away from technologies that rely on Java applets or Web Start applications

# Verify installed Java version and check for vulnerable releases
java -version

# For systems using alternatives, list all installed Java versions
update-alternatives --list java

# Disable Java browser plugins (Linux example)
# Remove or rename the Java plugin symlink
sudo rm /usr/lib/mozilla/plugins/libnpjp2.so