1. Introduction
Virtual JDBC Remote Code Execution is a critical vulnerability affecting all versions of Virtual JDBC. It allows an unauthenticated attacker with HTTP access to execute arbitrary code on affected systems. This poses a significant risk to the confidentiality, integrity and availability of data and services. Systems running Virtual JDBC are usually directly exposed to the internet or internal networks.
2. Technical Explanation
The vulnerability is caused by unsafe deserialization within Virtual JDBC. An attacker can send malicious serialised data to the endpoint, which will be processed without proper validation, leading to code execution. The attack requires HTTP access to the service and does not require authentication.
- Root cause: Unsafe deserialization of user-supplied input.
- Exploit mechanism: An attacker sends a crafted serialised Java object via an HTTP request to trigger remote code execution.
- Scope: All versions of Virtual JDBC are affected.
3. Detection and Assessment
To confirm vulnerability, check the version of Virtual JDBC running on your systems. A thorough assessment involves attempting a test deserialisation payload.
- Quick checks: Check application logs for any references to Virtual JDBC processing serialised data.
- Scanning: Nessus and other common scanners may have signatures related to Java deserialization vulnerabilities, but these are not always accurate. Use as an example only.
- Logs and evidence: Examine web server access logs for requests targeting the Virtual JDBC endpoint.
# No specific command available without knowing deployment details. Check application configuration files for Virtual JDBC version.4. Solution / Remediation Steps
The primary solution is to disable or filter access to the Virtual JDBC endpoint.
4.1 Preparation
- Ensure you have documented the original configuration for rollback purposes. A roll back plan is to restore the previous configuration or snapshot.
- Change windows may be required depending on service impact and approval processes.
4.2 Implementation
- Step 1: Block external access to the Virtual JDBC endpoint using firewall rules.
- Step 2: If Virtual JDBC is not required, disable the service entirely.
- Step 3: Review application code for any unnecessary use of Virtual JDBC and remove it if possible.
4.3 Config or Code Example
Before
# No specific configuration example available, as Virtual JDBC is typically integrated into larger applications. Access control will be managed by the hosting application or web server.After
# Example firewall rule (iptables):
# iptables -A INPUT -p tcp --dport 8080 -j DROP (assuming Virtual JDBC runs on port 8080)
4.4 Security Practices Relevant to This Vulnerability
Several security practices can help prevent this issue.
- Practice 1: Least privilege – limit network access to the service only to trusted sources.
4.5 Automation (Optional)
# No specific automation example available without knowing deployment details. Consider using Infrastructure as Code tools to manage firewall rules consistently.5. Verification / Validation
Confirm the fix by verifying that access to the Virtual JDBC endpoint is blocked and no longer allows code execution.
- Post-fix check: Attempt to access the Virtual JDBC endpoint from an untrusted source; confirm a connection refusal or error message.
- Re-test: Repeat the earlier detection steps (e.g., attempting deserialisation) and verify that they no longer succeed.
- Monitoring: Monitor web server logs for any attempts to access the blocked endpoint.
# Example curl command to test access (should fail):
# curl http://your-virtual-jdbc-host/endpoint
6. Preventive Measures and Monitoring
Update security baselines and add checks in CI pipelines.
- Baselines: Update your security baseline to include a requirement for blocking unnecessary network access to services like Virtual JDBC.
- Asset and patch process: Implement a regular review cycle of all deployed components, including third-party libraries, to ensure they are up to date with the latest security patches.
7. Risks, Side Effects, and Roll Back
Blocking access to Virtual JDBC may impact application functionality if it is still in use.
- Risk or side effect 2: Incorrect firewall rules could block legitimate traffic; review carefully.
- Roll back: Remove the firewall rule and restart the Virtual JDBC service if necessary. Restore the previous system snapshot if a more significant issue occurs.
8. References and Resources
- Vendor advisory or bulletin: No specific vendor advisory available, as Virtual JDBC is a general component.
- NVD or CVE entry: CVE-2019-0344
- Product or platform documentation relevant to the fix: https://wiki.scn.sap.com/wiki/pages/viewpage.action?pageId=523998017