Oracle Weblogic T3 XXE (CVE-2019-2647)
Description
Oracle WebLogic Server's T3 protocol, a proprietary implementation of Java RMI (Remote Method Invocation), is vulnerable to XML External Entity (XXE) injection (CVE-2019-2647). This vulnerability allows unauthenticated attackers to send specially crafted T3 protocol requests containing malicious XML payloads. Successful exploitation enables attackers to read arbitrary files from the server's file system, perform server-side request forgery (SSRF) attacks to access internal network resources, or cause denial-of-service conditions.
Remediation
Apply one or more of the following remediation measures immediately:
1. Apply Security Patches (Recommended):
• Upgrade to Oracle WebLogic Server versions that include the April 2019 Critical Patch Update or later
• Consult Oracle's Critical Patch Update Advisory for specific patch numbers and affected versions
• Test patches in a non-production environment before deploying to production systems
2. Disable T3 Protocol (If Not Required):
• If T3 protocol is not required for your application, disable it entirely in the WebLogic Server configuration
• Edit the domain configuration to remove T3 protocol listeners
3. Restrict T3 Protocol Access:
• Implement network-level access controls (firewall rules, security groups) to restrict T3 protocol access only to trusted IP addresses
• Use a connection filter to block unauthorized T3 connections
• Configure WebLogic Server to use T3S (T3 over SSL/TLS) instead of plain T3, and implement mutual authentication
4. Monitor and Detect:
• Enable WebLogic Server security logging to detect potential exploitation attempts
• Monitor for unusual T3 protocol traffic patterns or connections from unexpected sources