Oracle Weblogic T3 XXE (CVE-2019-2888)
Description
Oracle WebLogic Server's T3 protocol, a proprietary implementation of Java RMI (Remote Method Invocation), contains an XML External Entity (XXE) injection vulnerability tracked as CVE-2019-2888. This flaw allows attackers to process malicious XML input containing references to external entities, enabling unauthorized file access, server-side request forgery (SSRF), and denial-of-service conditions without requiring authentication.
Remediation
Take the following steps to remediate this vulnerability:
1. Apply Security Patches (Recommended)
Upgrade Oracle WebLogic Server to a version that includes the fix from Oracle Critical Patch Update - April 2019 or later. Consult Oracle's security advisory for specific patch versions applicable to your WebLogic release.
2. Disable or Restrict T3 Protocol Access
If immediate patching is not possible, implement the following mitigations:
• Disable T3 protocol if not required for your application
• Configure firewall rules to restrict T3 protocol access (default ports 7001, 7002) to only trusted IP addresses
• Use a connection filter to block unauthorized T3 connections by adding the following to your WebLogic configuration:
<security-configuration> <connection-filter>weblogic.security.net.ConnectionFilterImpl</connection-filter> <connection-filter-rules>[trusted-ip-range] * allow t3 t3s</connection-filter-rules> </security-configuration>
3. Network Segmentation
Ensure WebLogic servers are not directly exposed to the internet and are deployed within a protected network segment accessible only through properly configured reverse proxies or load balancers that do not forward T3 protocol traffic.