Oracle WebLogic Server is a core component in many enterprise Java applications, making it a frequent target for attackers. A notable vulnerability — CVE-2022-21353 — was disclosed affecting multiple versions, putting data integrity and server availability at risk. Here’s an exclusive, in-depth guide on what this vulnerability is, how it’s exploited, and what you can do to stay protected.

[References](#6)

1. What is CVE-2022-21353?

CVE-2022-21353 is a vulnerability in Oracle WebLogic Server, specifically in the “Core” component. Security researchers found that it can be exploited by attackers who have network access, via the T3 protocol, which is commonly used for WebLogic’s remote object access.

Authentication: Not required (Unauthenticated)

- References: Oracle Advisory


14.1.1..

Support for these versions means the vulnerability could affect both recent and older deployments.


Integrity Risk: Attackers can update, insert, or delete certain data without permission.

- Availability Risk: A successful attack can cause partial denial of service, slowing or crashing parts of your server.

CVSS Vector:
(CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L)

Impacts integrity and availability (not confidentiality)

4. How Exploits Work

A typical exploit involves sending crafted T3 requests that abuse flaws in the way WebLogic handles objects over the network. Attackers often write scripts in Python or use frameworks like Metasploit.

Here’s a simplified version of how attackers might exploit this with a Python script.

Sample Exploit Code

import socket

def send_t3_payload(target_ip, target_port):
    t3_handshake = (
        b't3 12.2.1.3.\n'
        b'AS:255\n'
        b'HL:19\n\n'
    )
    # Sample malicious payload (for demonstration)
    # Actual payloads are protocol-specific and require deep knowledge of T3
    payload = b"<malicious serialized Java object here>"

    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.connect((target_ip, target_port))
        s.sendall(t3_handshake)
        s.sendall(payload)
        resp = s.recv(1024)
        print(f"Response: {resp}")
        s.close()
    except Exception as e:
        print(f"Error: {e}")

if __name__ == "__main__":
    send_t3_payload("TARGET_IP_HERE", 7001)  # change IP and port as needed

Note:
- This is a simple PoC for educational purposes only. Real-world payloads are more complex and may use crafted Java serialized objects that exploit the vulnerability internally.


Oracle Official Patch

- Apply the patches provided in Oracle’s January 2022 Critical Patch Update.

Restrict T3 Access:

- Use firewalls or network controls to block access to TCP port 7001 (or your custom T3 port) from untrusted networks.

Example: Restrict T3 using a firewall

# Block T3 port (e.g., 7001) from public access
sudo iptables -A INPUT -p tcp --dport 7001 -s 10.../8 -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 7001 -j DROP

6. References

- Oracle January 2022 Critical Patch Update Advisory
- National Vulnerability Database entry for CVE-2022-21353
- Blog: Understanding WebLogic T3 Protocol Vulnerabilities
- WebLogic Server Security Best Practices

Conclusion

CVE-2022-21353 reminds us that enabling only necessary protocols, restricting network access, and keeping up with patches is critical for middleware like WebLogic. Even medium-severity bugs can have serious real-world consequences, especially in environments where attackers can reach exposed services. Patch, restrict, and monitor — stay safe out there!


*This post was written to give an easy-to-follow, exclusive look at CVE-2022-21353 for sysadmins and developers. Feel free to share this with your security team or IT leadership to drive faster patching and better security hygiene.*

Timeline

Published on: 01/19/2022 12:15:00 UTC
Last modified on: 01/24/2022 19:21:00 UTC