CVE-2020-2551
Oracle Fusion Middleware Unspecified Vulnerability
Description
CVE-2020-2551 is a critical remote code execution vulnerability in Oracle WebLogic Server, a widely deployed Java application server within Oracle Fusion Middleware. The flaw resides in the WLS Core Components and is exploitable by an unauthenticated attacker with network access via the IIOP protocol, allowing complete takeover of the affected WebLogic Server instance. Versions 10.3.6.0.0, 12.1.3.0.0, 12.2.1.3.0, and 12.2.1.4.0 are affected. CISA has added CVE-2020-2551 to its Known Exploited Vulnerabilities catalog, and the EPSS score of 94.4% (99th percentile) indicates near-certain exploitation activity, making immediate patching essential for any organization running affected WebLogic Server versions.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| oracle | weblogic server | 10.3.6.0.0; 12.1.3.0.0; 12.2.1.3.0; 12.2.1.4.0 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://www.oracle.com/security-alerts/cpujan2020.html(Patch, Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-2551(US Government Resource)
Weakness Type
No specific CWE has been assigned to CVE-2020-2551. The vulnerability affects the WLS Core Components of Oracle WebLogic Server and is exploitable through the IIOP (Internet Inter-ORB Protocol) interface, enabling unauthenticated remote attackers to execute arbitrary code and achieve full server takeover.
Impact Analysis
CVE-2020-2551 carries a CVSS v3.1 base score of 9.8 (Critical severity), placing it at the highest risk tier. The vulnerability is remotely exploitable over the network via the IIOP protocol with low attack complexity, requiring no special conditions for successful exploitation. Privileges Required (None): No authentication credentials are needed, allowing any attacker with network access to the IIOP listener to launch an attack. User Interaction (None): The attack is fully automated and requires no action from a legitimate user. Confidentiality (High): A successful attack provides the attacker with complete read access to all data accessible by the WebLogic Server process, including application data, configuration files, database credentials, and potentially sensitive business information. Integrity (High): The attacker can modify application code, deploy malicious web applications, alter database records, and manipulate server configurations. Availability (High): Full denial of service is possible, as the attacker can shut down or destabilize the WebLogic Server instance. The EPSS score of 94.4% indicates near-certain active exploitation, making this vulnerability a top-priority remediation target for organizations running Oracle WebLogic Server.
Exploit Maturity
CISA has confirmed active exploitation of CVE-2020-2551 in the wild by adding it to the Known Exploited Vulnerabilities catalog with a remediation deadline of December 7, 2023. The EPSS score of 94.4% (99th percentile) indicates near-certain exploitation activity, placing it among the most actively targeted vulnerabilities in the threat landscape. While no specific exploit code is tagged in the provided references, the easily exploitable nature of the IIOP-based attack vector, combined with the critical severity and high prevalence of WebLogic Server in enterprise environments, makes this vulnerability an attractive target for threat actors conducting initial access operations.
Remediation
- Apply the Oracle Critical Patch Update (CPU) for January 2020 immediately. Install the security patch referenced in the Oracle Security Alert for all affected WebLogic Server versions (10.3.6.0.0, 12.1.3.0.0, 12.2.1.3.0, 12.2.1.4.0). Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- Disable the IIOP protocol on WebLogic Server if it is not required for business operations. Navigate to the WebLogic Server Administration Console, select the affected server, go to Protocols > IIOP, and uncheck "Enable IIOP." This eliminates the attack vector entirely for environments that do not use CORBA/IIOP communication.
- Restrict network access to the IIOP listener port. Implement firewall rules to block external access to the IIOP port (typically 7001 or as configured) and limit access to trusted internal IP addresses only. Use network segmentation to isolate WebLogic Server instances from internet-facing networks.
- Monitor for signs of compromise. Review WebLogic Server logs for unusual IIOP connection attempts, unexpected application deployments, or unauthorized configuration changes. Check for newly created user accounts, web shells, or suspicious outbound network connections from the server.
- Upgrade to a supported WebLogic Server version that includes the latest security patches. Oracle WebLogic Server 10.3.6.0.0 and 12.1.3.0.0 are legacy versions — plan a migration to a currently supported version to receive ongoing security updates.
Technical Details
CVE-2020-2551 is a deserialization-related vulnerability in the WLS Core Components of Oracle WebLogic Server that is exploitable through the IIOP (Internet Inter-ORB Protocol) interface. IIOP is a CORBA-based communication protocol used for distributed object communication, and WebLogic Server exposes an IIOP listener that processes incoming object requests. The vulnerability allows an unauthenticated attacker to send specially crafted IIOP requests to the WebLogic Server, which are processed in a way that leads to arbitrary code execution in the context of the server process. Attack Vector (Network): The IIOP listener is a network-accessible service, typically exposed on the same port as the WebLogic HTTP listener (default 7001), allowing remote exploitation without physical access. Attack Complexity (Low): The attack requires no special conditions, timing, or environmental prerequisites — a single crafted IIOP request is sufficient to trigger the vulnerability. Scope (Unchanged): While the impact is confined to the WebLogic Server process, the high privileges of this process and its access to application data, databases, and internal networks make the effective blast radius significant. Successful exploitation results in complete takeover of the Oracle WebLogic Server instance, with full control over confidentiality, integrity, and availability.
Frequently Asked Questions
Is CVE-2020-2551 being actively exploited?
Yes, CVE-2020-2551 is being actively exploited in the wild. CISA has added it to the Known Exploited Vulnerabilities catalog with a remediation deadline of December 7, 2023. The EPSS score of 94.4% (99th percentile) confirms near-certain exploitation activity, making immediate patching critical.
What products are affected by CVE-2020-2551?
CVE-2020-2551 affects Oracle WebLogic Server versions 10.3.6.0.0, 12.1.3.0.0, 12.2.1.3.0, and 12.2.1.4.0 within Oracle Fusion Middleware. The vulnerability is specifically in the WLS Core Components and is exploitable via the IIOP protocol.
How do I fix CVE-2020-2551?
Apply the Oracle Critical Patch Update (CPU) from January 2020 as described in the Oracle Security Alert. If immediate patching is not feasible, disable the IIOP protocol on the WebLogic Server or restrict network access to the IIOP listener port to trusted internal addresses only.
How severe is CVE-2020-2551?
CVE-2020-2551 is rated Critical with a CVSS v3.1 base score of 9.8 out of 10. It requires no authentication, no user interaction, and can be exploited remotely with low complexity. The EPSS score of 94.4% (99th percentile) indicates it is among the most actively exploited vulnerabilities, demanding immediate remediation.
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