CVE-2021-2142: Oracle WebLogic Server Auth Bypass Flaw

CVE-2021-2142 Overview

A vulnerability exists in the Oracle WebLogic Server product of Oracle Fusion Middleware, specifically affecting the Console component. This easily exploitable vulnerability allows an unauthenticated attacker with network access via HTTP to compromise Oracle WebLogic Server. The vulnerability requires human interaction from a person other than the attacker, and while the vulnerability resides in Oracle WebLogic Server, successful attacks may significantly impact additional products beyond the vulnerable component itself.

Successful exploitation of this vulnerability can result in unauthorized update, insert, or delete access to some Oracle WebLogic Server accessible data, as well as unauthorized read access to a subset of Oracle WebLogic Server accessible data. This poses both confidentiality and integrity risks to affected deployments.

Critical Impact

Unauthenticated attackers can exploit this vulnerability remotely via HTTP to gain unauthorized data access and modification capabilities in Oracle WebLogic Server environments.

Affected Products

• Oracle WebLogic Server version 10.3.6.0.0
• Oracle Fusion Middleware (WebLogic Server Console component)

Discovery Timeline

• 2021-04-22 - CVE CVE-2021-2142 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2021-2142

Vulnerability Analysis

This vulnerability affects the Console component of Oracle WebLogic Server, which is a critical administrative interface used to manage WebLogic Server domains, deploy applications, and configure server resources. The vulnerability is classified as easily exploitable, meaning that the attack complexity is low and does not require sophisticated techniques or special conditions.

The scope of this vulnerability is notable because attacks against Oracle WebLogic Server may significantly impact additional products (changed scope). This characteristic indicates that the vulnerable component and the impacted component are different, which is particularly concerning in enterprise environments where WebLogic Server often serves as a foundational middleware platform supporting multiple business applications.

The vulnerability allows both unauthorized read access and unauthorized modification capabilities (insert, update, delete) to accessible data, though the impact is limited to a subset of data rather than complete compromise.

Root Cause

While specific root cause details are not publicly disclosed by Oracle (classified as NVD-CWE-noinfo), the vulnerability characteristics suggest a web application security flaw in the WebLogic Console component. Given that exploitation requires user interaction and occurs via HTTP with network access, this is consistent with vulnerabilities such as Cross-Site Scripting (XSS) or Cross-Site Request Forgery (CSRF) patterns that affect web-based administrative interfaces.

The Console component processes HTTP requests and the vulnerability allows unauthenticated attackers to leverage human interaction to perform unauthorized operations, which aligns with client-side web vulnerabilities that trick authenticated users into performing actions on behalf of the attacker.

Attack Vector

The attack vector for CVE-2021-2142 operates over the network via HTTP protocol. An attacker does not require authentication to exploit this vulnerability; however, successful exploitation depends on user interaction from a person other than the attacker.

The typical attack scenario involves:

1. An attacker crafts a malicious request or link targeting the WebLogic Console component
2. The attacker delivers this payload to a victim user who has access to the WebLogic administrative interface
3. When the victim interacts with the malicious content, the attacker gains unauthorized access to read or modify data
4. Due to the changed scope characteristic, the impact may extend beyond WebLogic Server to other integrated systems

This vulnerability is particularly dangerous in environments where WebLogic Server administrators may be targeted through phishing or social engineering techniques to trigger the exploitation chain.

Detection Methods for CVE-2021-2142

Indicators of Compromise

• Unusual HTTP requests to WebLogic Console endpoints from unexpected sources or containing suspicious parameters
• Unexpected data modifications or access patterns in WebLogic Server-managed resources
• User reports of being redirected to malicious sites after accessing WebLogic Console
• Anomalous session activity or unauthorized administrative actions following user interaction with external links

Detection Strategies

• Implement web application firewall (WAF) rules to inspect and filter suspicious requests to WebLogic Console endpoints
• Enable comprehensive HTTP access logging for all WebLogic Console traffic and monitor for anomalous patterns
• Deploy network-based intrusion detection systems (IDS) with signatures targeting known WebLogic exploitation techniques
• Configure SentinelOne Singularity platform to monitor WebLogic Server processes for suspicious behavior and network activity

Monitoring Recommendations

• Establish baseline behavior for WebLogic Console access patterns and alert on deviations
• Monitor WebLogic Server audit logs for unauthorized data access or modification attempts
• Track administrative user sessions and correlate with external link clicks or email interactions
• Implement user behavior analytics to identify potential social engineering attacks targeting WebLogic administrators

How to Mitigate CVE-2021-2142

Immediate Actions Required

• Apply the Oracle Critical Patch Update from April 2021 immediately to affected WebLogic Server version 10.3.6.0.0
• Restrict network access to the WebLogic Console to trusted administrative networks only
• Implement strong content security policies and input validation at the network edge
• Educate WebLogic administrators about phishing and social engineering risks

Patch Information

Oracle has addressed this vulnerability in the Oracle Critical Patch Update April 2021. Organizations running Oracle WebLogic Server version 10.3.6.0.0 should apply this critical patch update immediately.

The April 2021 CPU contains fixes for multiple vulnerabilities affecting Oracle Fusion Middleware products. Organizations should review the complete advisory to identify all applicable patches for their environment and plan a comprehensive update strategy.

Workarounds

• Restrict WebLogic Console access to internal networks only, blocking external HTTP access to administrative interfaces
• Implement a reverse proxy with additional security controls in front of WebLogic Console
• Enable multi-factor authentication for all administrative access to reduce the risk of credential-based attacks
• Consider temporarily disabling WebLogic Console access and managing servers via command-line tools until patches are applied

# Configuration example: Restrict WebLogic Console access via network ACLs
# Add to your firewall configuration to limit Console access

# Allow Console access only from trusted admin network
iptables -A INPUT -p tcp --dport 7001 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 7001 -j DROP

# Alternatively, configure WebLogic Server to bind Console to internal interface only
# In config.xml, set listen-address to internal IP
# <listen-address>10.0.0.10</listen-address>