Overview
Oracle WebLogic Server contains a critical remote code execution vulnerability in its IIOP (Internet Inter-ORB Protocol) implementation that allows unauthenticated attackers to execute arbitrary code on the server. The vulnerability exists in the deserialization of untrusted data received over the network, affecting multiple versions of WebLogic Server across different product lines. The vulnerability was disclosed on January 15, 2020. CISA has identified CVE-2020-2551 as being exploited but is not currently known to be used in ransomware campaigns.
Technical details
Oracle WebLogic Server is vulnerable to remote code execution through its IIOP (Internet Inter-ORB Protocol) implementation. The vulnerability stems from improper validation and deserialization of serialized Java objects received over IIOP connections. An attacker can craft a malicious serialized object that, when deserialized by the server, executes arbitrary code with the privileges of the WebLogic process. The IIOP protocol is enabled by default on WebLogic instances, making the vulnerability exploitable over the network without authentication.
The vulnerability is classified as CWE-502 (Deserialization of Untrusted Data) andCWE-94 (Improper Control of Generation of Code ('Code Injection')) .
The vulnerability has received a CVSS v3.1 base score of 9.8 (CRITICAL) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, indicating its critical nature.
Impact
An unauthenticated remote attacker can execute arbitrary code on the affected WebLogic server with the same privileges as the WebLogic process. This can lead to complete system compromise, including data theft, malware installation, lateral movement within the network, denial of service, and use of the compromised server as a pivot point for further attacks. The vulnerability has been widely exploited in the wild and is a critical security issue for any organization running affected WebLogic versions.
Mitigation and workarounds
Oracle released Critical Patch Update (CPU) on January 14, 2020. Apply the appropriate patch bundle for your WebLogic version. Download from My Oracle Support (MOS) patch number 30660046 or through the WebLogic Patch Advisor. The following versions include the necessary fixes: WebLogic Server 10.3.6.0.200121, WebLogic Server 12.1.3.0.200121, WebLogic Server 12.2.1.3.200121, WebLogic Server 12.2.1.4.200121.
As temporary workarounds: disable iiop protocol if not required for your environment. set the iiop listen port to null or configure network firewall rules to restrict iiop port access (default ports 7001, 7002) to trusted sources only.; implement network-level access controls to restrict connections to iiop ports. use firewalls or network segmentation to allow only trusted internal networks to access the iiop protocol.; implement java deserialization filters using weblogic's deserialization filter capabilities (available in later versions or via patches). configure filters to whitelist safe classes and block dangerous gadget chain classes., and remove unnecessary libraries from weblogic classpath that could be used for gadget chains (e.g., commons-collections if not required by applications)..
CISA's recommendation: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Additional resources
Source: This report was generated using AI
