CVE-2020-14556: Oracle OpenJDK Auth Bypass Vulnerability

CVE-2020-14556 Overview

CVE-2020-14556 is a vulnerability in the Java SE and Java SE Embedded products from Oracle, specifically affecting the Libraries component. This flaw allows an unauthenticated attacker with network access to compromise affected Java installations through multiple protocols. Successful exploitation can result in unauthorized update, insert, or delete access to some accessible data, as well as unauthorized read access to a subset of data managed by the affected Java runtime environments.

The vulnerability applies to both client and server deployments of Java and can be exploited through multiple attack vectors including sandboxed Java Web Start applications, sandboxed Java applets, and by supplying malicious data to APIs in the Libraries component without using sandboxed environments (such as through a web service).

Critical Impact
Attackers can gain unauthorized read and write access to Java application data through network-based attacks targeting the Libraries component, affecting both client-side and server-side Java deployments.

Affected Products

Oracle JDK 8u251, 11.0.7, 14.0.1
Oracle JRE 8u251, 11.0.7, 14.0.1
Oracle OpenJDK 8 (multiple milestones and updates through 8u252), 11 through 11.0.7, 13 through 13.0.3, 14.0.1
Java SE Embedded 8u251
Fedora 31, 32
openSUSE Leap 15.1, 15.2
Debian Linux 9.0, 10.0
Ubuntu Linux 16.04 ESM, 18.04 LTS, 20.04 LTS
NetApp products: 7-Mode Transition Tool, Active IQ Unified Manager, Cloud Backup, Cloud Secure Agent, E-Series Performance Analyzer, E-Series SANtricity OS Controller, E-Series SANtricity Web Services, OnCommand Insight, OnCommand Workflow Automation, SANtricity Unified Manager, SnapManager, SteelStore Cloud Integrated Storage, StorageGRID

Discovery Timeline

July 15, 2020 - CVE-2020-14556 published to NVD
May 27, 2025 - Last updated in NVD database

Technical Details for CVE-2020-14556

Vulnerability Analysis

This vulnerability resides within the Libraries component of Oracle Java SE and Java SE Embedded. The flaw enables an unauthenticated remote attacker to compromise the integrity and confidentiality of data accessible to Java applications. While the vulnerability is classified as difficult to exploit, requiring specific conditions to be met, its network accessibility makes it a concern for organizations running vulnerable Java versions in internet-facing or network-accessible environments.

The impact is constrained to partial compromise of both confidentiality and integrity, meaning attackers can read and modify a subset of application data but cannot achieve full system compromise or cause availability impacts through this vulnerability alone.

Root Cause

The vulnerability stems from improper handling within the Libraries component of the Java runtime environment. While Oracle has not disclosed the specific technical details of the flaw, it affects how the Libraries component processes certain operations, allowing unauthorized data access when specific conditions are met during network-based interactions.

Attack Vector

The vulnerability can be exploited through multiple network-based attack vectors:

Java Web Start Applications: Attackers can craft malicious sandboxed Java Web Start applications that exploit the vulnerability when executed by victims
Java Applets: Sandboxed Java applets running in web browsers can be weaponized to trigger the vulnerability
Direct API Exploitation: Data can be supplied directly to vulnerable APIs in the Libraries component through web services or other network interfaces, bypassing the need for sandboxed application delivery

The attack requires network access and exploitation is considered difficult, as the attacker must overcome certain technical barriers to successfully leverage the flaw.

Detection Methods for CVE-2020-14556

Indicators of Compromise

Unusual network traffic patterns targeting Java-based web services or applications
Unexpected Java Web Start application execution or applet loading from untrusted sources
Anomalous data access or modification patterns in Java application logs
Evidence of unauthorized API calls to Libraries component functions

Detection Strategies

Monitor Java application logs for unusual data access patterns or unexpected API invocations
Implement network intrusion detection rules to identify suspicious traffic targeting Java services
Deploy endpoint detection solutions capable of monitoring Java runtime behavior for anomalous activity
Conduct regular vulnerability scans to identify systems running affected Java versions

Monitoring Recommendations

Enable comprehensive logging for Java applications, particularly those exposed to network access
Establish baseline behavior patterns for Java Web Start and applet usage within the environment
Monitor for unexpected outbound connections from Java processes
Implement alerting for attempts to access Java applications from unauthorized network sources

How to Mitigate CVE-2020-14556

Immediate Actions Required

Inventory all systems running Oracle Java SE, Java SE Embedded, or OpenJDK to identify affected versions
Prioritize patching for systems with network-accessible Java applications or services
Consider disabling Java Web Start and applet support where not required for business operations
Apply network segmentation to limit exposure of vulnerable Java installations

Patch Information

Oracle addressed this vulnerability in the July 2020 Critical Patch Update (CPU). Organizations should apply the latest available patches from the Oracle Security Alert. For Linux distributions, updated packages are available through:

NetApp customers should review the NetApp Security Advisory NTAP-20200717-0005 for guidance on affected NetApp products.

Workarounds

Restrict network access to Java applications and services using firewalls and access control lists
Disable Java Web Start and browser-based Java applet execution where not business-critical
Implement web application firewalls (WAF) to filter potentially malicious requests to Java-based web services
Consider running Java applications in isolated network segments with strict ingress and egress controls

bash

# Example: Disable Java Web Start associations (Windows)
# Remove file associations for .jnlp files
assoc .jnlp=

# Example: Check current Java version on Linux
java -version

# Update Java on Ubuntu/Debian systems
sudo apt update && sudo apt install openjdk-11-jdk