CVE-2020-2968: Oracle Database Java VM Privilege Escalation

CVE-2020-2968 Overview

CVE-2020-2968 is a high severity vulnerability in the Java VM component of Oracle Database Server. The flaw affects supported versions 11.2.0.4, 12.1.0.2, 12.2.0.1, 18c, and 19c. A low-privileged attacker holding Create Session and Create Procedure privileges with network access through multiple protocols can compromise the Java VM. Exploitation is difficult and requires human interaction from a user other than the attacker. Successful exploitation results in takeover of the Java VM and can significantly impact additional products beyond the vulnerable component itself.

Critical Impact
Successful exploitation results in full takeover of the Oracle Database Java VM, with confidentiality, integrity, and availability impacts that can cross security scopes into other connected products.

Affected Products

Oracle Database Server 11.2.0.4
Oracle Database Server 12.1.0.2, 12.2.0.1
Oracle Database Server 18c and 19c

Discovery Timeline

2020-07-15 - Oracle published the July 2020 Critical Patch Update addressing CVE-2020-2968
2020-07-15 - CVE-2020-2968 published to NVD
2024-11-21 - Last updated in NVD database

Technical Details for CVE-2020-2968

Vulnerability Analysis

The vulnerability resides in the Java VM component embedded in Oracle Database Server. Oracle's Java VM enables stored procedures and database logic to be written in Java and executed inside the database engine. The flaw allows a low-privileged database user to escalate access and take over the Java VM runtime.

The vulnerability has a scope change, meaning compromise of the Java VM can affect resources beyond its own security boundary. An attacker reaching this surface gains the ability to influence confidentiality, integrity, and availability of related Oracle products. Exploit complexity is high, and successful attacks require human interaction from a separate user, which limits opportunistic exploitation.

No public proof-of-concept exploit has been released, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. The EPSS score reflects a probability of 1.706% at the 82.5 percentile, indicating elevated relative exploitation interest compared to most CVEs.

Root Cause

The specific weakness is categorized as NVD-CWE-noinfo because Oracle did not disclose internal technical details. Based on the advisory, the issue is reachable from any database session that can create procedures, indicating insufficient isolation or validation within the Java VM execution path when handling attacker-controlled procedure logic combined with victim-triggered actions.

Attack Vector

The attack vector is network-based across multiple Oracle Database protocols. The attacker must already authenticate to the database with Create Session and Create Procedure privileges. The attacker stages malicious Java content within the database and then relies on a separate, higher-privileged or unwitting user to interact with it, completing the chain that compromises the Java VM. No verified public exploit code exists for this issue. Refer to the Oracle Security Alert July 2020 for vendor-supplied technical context.

Detection Methods for CVE-2020-2968

Indicators of Compromise

Unexpected creation or modification of Java classes, sources, or resources inside the database by accounts with only Create Session and Create Procedure privileges.
Anomalous execution of Java stored procedures invoked by administrative users shortly after procedure creation by low-privileged accounts.
Java VM runtime errors or privilege transitions logged in Oracle audit trails that correlate with unusual session activity.

Detection Strategies

Enable Oracle unified auditing for CREATE PROCEDURE, CREATE JAVA, and ALTER JAVA statements and review entries from non-administrative accounts.
Baseline which database accounts legitimately publish Java code, and alert on deviations involving service or application users.
Correlate Java VM error events in alert.log with session metadata to identify exploitation attempts that fail or partially succeed.

Monitoring Recommendations

Forward Oracle audit and listener logs to a centralized analytics platform for cross-session correlation and retention.
Monitor outbound network connections initiated by database server processes, which may indicate post-exploitation activity from a compromised Java VM.
Track privilege grants involving JAVAUSERPRIV, JAVASYSPRIV, and JAVADEBUGPRIV to detect attempts to expand the Java VM attack surface.

How to Mitigate CVE-2020-2968

Immediate Actions Required

Apply the Oracle July 2020 Critical Patch Update to all affected Oracle Database Server instances on versions 11.2.0.4, 12.1.0.2, 12.2.0.1, 18c, and 19c.
Inventory database accounts holding Create Session and Create Procedure privileges and revoke them where not required for business operations.
Audit existing Java objects in the database for unauthorized or unexpected entries before and after patching.

Patch Information

Oracle released fixes for CVE-2020-2968 as part of the July 2020 Critical Patch Update. Administrators should review the Oracle Security Alert July 2020 and apply the corresponding database patch set for their version and platform. Patching requires standard Oracle Database maintenance procedures including OPatch application and post-install datapatch execution.

Workarounds

Restrict CREATE PROCEDURE and Java-related privileges to a minimal set of trusted, well-audited accounts until patches are applied.
Disable or restrict access to the Java VM in databases where Java stored procedures are not required for application functionality.
Enforce network segmentation so that only application servers can reach the database listener, reducing the pool of users that could authenticate and stage an attack.

bash

# Example: revoke Java-related privileges from a low-privileged account
sqlplus / as sysdba <<'EOF'
REVOKE CREATE PROCEDURE FROM app_low_priv_user;
REVOKE JAVAUSERPRIV   FROM app_low_priv_user;
REVOKE JAVASYSPRIV    FROM app_low_priv_user;
REVOKE JAVADEBUGPRIV  FROM app_low_priv_user;
EXIT
EOF