CVE-2023-45235: Buffer Overflow Vulnerability in EDK2’s Network Package

Overview

The cybersecurity landscape is constantly evolving with new vulnerabilities being discovered frequently. Among the latest is CVE-2023-45235, a substantial buffer overflow vulnerability found in EDK2’s Network Package that affects how it handles the Server ID option from a DHCPv6 proxy Advertise message. This vulnerability is significant as it can be exploited by attackers to gain unauthorized access to systems. Given the ubiquity of network devices and their role in modern infrastructures, a vulnerability like this can pose serious security risks, potentially leading to system compromise and data leakage.

Vulnerability Summary

CVE ID: CVE-2023-45235
Severity: High (8.3 CVSS Score)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Unauthorized access, potential system compromise, and data leakage

Affected Products

Product | Affected Versions

EDK2 Network Package | All versions prior to patch

How the Exploit Works

The vulnerability stems from a flaw in the Network Package’s handling of the Server ID option from a DHCPv6 proxy Advertise message. When the package processes this data, a buffer overflow can occur. This happens when more data is put into a buffer than it can handle, causing an overflow of data. The excess data can overwrite adjacent memory locations, leading to erratic program behavior, crashes, or, in the worst-case scenario, the execution of malicious code. An attacker can exploit this flaw by sending a specially crafted DHCPv6 proxy Advertise message to trigger the overflow and gain unauthorized access to the system.

Conceptual Example Code

Here’s a conceptual example of how the vulnerability might be exploited. In this case, an attacker could craft a malicious DHCPv6 proxy Advertise message to trigger the buffer overflow:

POST /DHCPv6/Advertise HTTP/1.1
Host: target.example.com
Content-Type: application/dhcp
{
"server_id": "OVERFLOW DATA"
}

In the above example, “OVERFLOW DATA” represents a large amount of data designed to exceed the buffer limit, causing overflow and potentially executing malicious code.
Please note that this is a simplified and conceptual example. Real-world exploits would likely be more complex and could involve additional techniques such as heap spraying or return-oriented programming.