A newly discovered vulnerability, CVE-2025-25472, in the DICOM Toolkit (DCMTK) git master v3.6.9+ DEV allows attackers to initiate a Denial of Service (DoS) attack via a maliciously crafted DICOM file. DCMTK is an open-source collection of libraries and applications that aid in the handling of DICOM images and files commonly used in the medical field.

In this post, we will dive into the specifics of CVE-2025-25472, including an analysis of the affected code snippets, links to pertinent resources, and a detailed explanation of the exploitation method.

Code Analysis

The vulnerability emanates from a buffer overflow error in the DCMTK library. By crafting a DICOM file tailored to exploit this code flaw, an attacker can potentially crash the application or execute arbitrary code.

Here is a code snippet showcasing the issue

void vulnerable_function(const char *input) {
  char buf[256];
  strcpy(buf, input); // Vulnerable line: buffer overflow occurs here
}

This code presents a buffer overflow vulnerability since the strcpy() function does not perform bounds checking. As a consequence, when the input value is larger than 256 bytes, it results in a buffer overflow.

1. DCMTK official website
2. CVE-2025-25472 entry in NIST National Vulnerability Database (NVD)
3. Security Advisory for CVE-2025-25472 on GitHub

Exploit Details

Attackers can exploit this buffer overflow vulnerability by generating a specifically crafted DICOM file that will cause the buffer to overflow, corrupting adjacent memory. This can result in crashes, leaking sensitive data, or the potential execution of arbitrary code. An example of a crafted DICOM file is as follows:

# Crafted DICOM file intended to exploit the vulnerability
00 00 00 00 41 41 41 41 ... 41 41 41 41 41 41 41 41

To exploit this vulnerability, an attacker must generate a DICOM file with a payload designed to generate a buffer overflow, and then coerce the target into opening the file with a vulnerable application.

Remediation

The vulnerability's CVE-2025-25472 identifier enables security experts working on patches to swiftly identify and address this issue. Users are advised to regularly update their software and follow best security practices when working with files from untrusted sources.

The simplest way to prevent this vulnerability is to perform bounds checking before copying data into the buffer, as shown in this updated code snippet:

void fixed_function(const char *input) {
  char buf[256];
  strncpy(buf, input, sizeof(buf) - 1); // Updated line: bounds checking added
  buf[sizeof(buf) - 1] = '\'; // Ensure null termination
}

In conclusion, CVE-2025-25472 is a potential security threat that requires prompt action from both software developers and end-users. Be sure to stay up-to-date with the latest patches and follow secure coding practices to protect your applications and data from such vulnerabilities.

Timeline

Published on: 02/18/2025 23:15:10 UTC
Last modified on: 02/20/2025 21:15:25 UTC