CVE-2021-2334: Oracle Database Auth Bypass Vulnerability

CVE-2021-2334 Overview

CVE-2021-2334 is a vulnerability affecting the Data Redaction component of Oracle Database Enterprise Edition. This security flaw allows a low-privileged attacker with Create Session privileges to compromise the integrity of redacted data through network access via Oracle Net. The vulnerability requires human interaction from a person other than the attacker for successful exploitation, making it a socially-engineered attack vector combined with technical access.

Critical Impact

Successful exploitation enables unauthorized update, insert, or delete access to Oracle Database Enterprise Edition Data Redaction accessible data, potentially compromising data integrity protections designed to mask sensitive information.

Affected Products

• Oracle Database Enterprise Edition 12.1.0.2
• Oracle Database Enterprise Edition 12.2.0.1
• Oracle Database Enterprise Edition 19c

Discovery Timeline

• 2021-07-21 - CVE-2021-2334 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2021-2334

Vulnerability Analysis

This vulnerability resides in the Data Redaction component of Oracle Database Enterprise Edition, a feature designed to mask sensitive data in real-time when it is accessed by applications or users. The flaw allows attackers with minimal privileges (Create Session) to bypass or manipulate the data redaction policies through network-based interactions.

The attack requires network access via Oracle Net, Oracle's proprietary networking protocol for database communications. While the vulnerability is easily exploitable from a technical standpoint, it requires some form of human interaction, suggesting a component of social engineering or user-assisted exploitation may be necessary.

The impact is limited to integrity violations—attackers cannot read confidential data (no confidentiality impact) or cause service disruptions (no availability impact). However, the ability to modify, insert, or delete redacted data entries undermines the fundamental purpose of data redaction controls.

Root Cause

The root cause stems from insufficient authorization checks or improper access control mechanisms within the Data Redaction component. When a low-privileged user with Create Session privileges interacts with the system under specific conditions requiring user interaction, the component fails to properly validate permissions for data modification operations on redacted data sets.

Attack Vector

The attack is network-based, leveraging Oracle Net protocol connectivity. An attacker with valid database credentials (Create Session privilege) can craft requests that, when combined with user interaction from another party, bypass the expected data protection controls of the Data Redaction feature.

The attack flow involves:

1. Establishing a network connection to the Oracle Database via Oracle Net
2. Authenticating with minimal privileges (Create Session)
3. Exploiting the Data Redaction component through manipulated requests
4. Achieving unauthorized data modification once human interaction occurs

Detection Methods for CVE-2021-2334

Indicators of Compromise

• Unexpected modifications to data protected by Data Redaction policies
• Unusual session activity from low-privileged accounts targeting redacted tables
• Anomalous Oracle Net traffic patterns from authenticated sessions

Detection Strategies

• Monitor Oracle audit logs for unusual DML operations (UPDATE, INSERT, DELETE) from sessions with only Create Session privileges
• Implement database activity monitoring to track access patterns to tables with Data Redaction policies
• Review Oracle listener logs for suspicious connection patterns via Oracle Net

Monitoring Recommendations

• Enable Oracle Database Auditing for all Data Redaction policy changes and violations
• Configure alerts for modifications to redacted data columns from non-administrative accounts
• Deploy SentinelOne Singularity platform to monitor database server endpoints for anomalous process behavior

How to Mitigate CVE-2021-2334

Immediate Actions Required

• Apply the Oracle Critical Patch Update from July 2021 immediately to all affected database instances
• Review and restrict Create Session privileges to only essential users
• Audit existing Data Redaction policies to ensure proper configuration
• Implement network segmentation to limit Oracle Net access to trusted sources

Patch Information

Oracle has addressed this vulnerability in the Oracle Critical Patch Update July 2021. Database administrators should download and apply the appropriate patches for their specific Oracle Database version (12.1.0.2, 12.2.0.1, or 19c). The patching process should follow Oracle's standard patch application procedures, including testing in non-production environments first.

Workarounds

• Restrict network access to Oracle Database servers using firewall rules to limit Oracle Net connectivity
• Implement additional application-layer access controls for sensitive data beyond Data Redaction
• Review and minimize the number of accounts with Create Session privileges
• Enable Oracle Database Vault for additional access control layers on sensitive data