CVE-2025-3481: Stack-based Buffer Overflow in MedDream PACS Server

CRITICAL SECURITY ALERT - CVE-2025-3481 requires immediate attention from all healthcare organizations using MedDream PACS Server.

Executive Summary

This vulnerability poses severe risks to healthcare infrastructure, potentially compromising patient data confidentiality and healthcare system operations. The flaw affects DICOM file parsing and requires no authentication for exploitation.

Impact Assessment

Technical Deep Dive

Vulnerability Breakdown

The core of CVE-2025-3481 is a Stack-based Buffer Overflow vulnerability within the MedDream PACS Server’s DICOM file parsing engine.

A Real-World Analogy for Stack-based Buffer Overflow

Imagine a medical filing cabinet with fixed-size drawers designed to hold a specific number of patient files. The filing system has a clerk who processes incoming files and places them in the appropriate drawer. However, if someone sends an unusually large batch of files for a single drawer, and the clerk doesn’t check if the drawer has enough space, the files will overflow and spill into adjacent drawers, potentially corrupting other patient records or even damaging the filing system’s organizational structure.

In this analogy, the filing cabinet drawer is the stack buffer, the patient files are the DICOM data, and the clerk is the parsing function that fails to validate input size, leading to memory corruption that can compromise the entire system.

The Exploit Chain: From DICOM Processing to Code Execution

This vulnerability is triggered by insufficient bounds checking during DICOM file processing:

1. Malicious DICOM Creation: The attacker crafts a malicious DICOM file with oversized data fields designed to overflow the fixed-size stack buffer during parsing.

2. File Processing: The MedDream PACS Server processes the DICOM file without proper validation of field lengths, copying data to a stack-allocated buffer.

3. Stack Overflow: The oversized data overwrites adjacent memory locations on the stack, including return addresses and local variables.

4. Control Flow Hijacking: By carefully crafting the overflow data, attackers can overwrite the return address to redirect execution to their malicious code, achieving remote code execution.

Simplified Proof-of-Concept

The following conceptual approach illustrates the logic behind the exploit. Note: This is a simplified example for educational purposes.

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/*
CVE-2025-3481 Stack Buffer Overflow Proof of Concept
WARNING: This code is for educational and authorized testing purposes only.
*/

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

// Vulnerable function similar to the one in MedDream PACS
void vulnerable_dicom_parser(char *dicom_data) {
    char buffer[256];  // Fixed-size stack buffer
    
    // VULNERABLE: No bounds checking before copying data
    strcpy(buffer, dicom_data);  // Stack overflow occurs here
    
    printf("Processing DICOM data: %s\n", buffer);
}

// Demonstration of secure parsing
void secure_dicom_parser(char *dicom_data, size_t data_len) {
    char buffer[256];
    
    // Secure: Check input size before copying
    if (data_len >= sizeof(buffer)) {
        printf("Error: DICOM data too large for buffer\n");
        return;
    }
    
    // Use safe string functions
    strncpy(buffer, dicom_data, sizeof(buffer) - 1);
    buffer[sizeof(buffer) - 1] = '\0';  // Ensure null termination
    
    printf("Safely processing DICOM data: %s\n", buffer);
}

int main() {
    // Example of malicious DICOM data (oversized)
    char malicious_data[512];
    memset(malicious_data, 'A', sizeof(malicious_data) - 1);
    malicious_data[sizeof(malicious_data) - 1] = '\0';
    
    printf("CVE-2025-3481 Buffer Overflow Analysis\n");
    printf("Demonstrating vulnerable vs secure parsing\n\n");
    
    // This would cause a buffer overflow in real scenario
    printf("Secure parser handling oversized data:\n");
    secure_dicom_parser(malicious_data, strlen(malicious_data));
    
    return 0;
}

Root Cause and Patch Analysis

The root cause of CVE-2025-3481 lies in the MedDream PACS Server’s DICOM file parsing routines, which fail to validate input length before copying data to fixed-size stack buffers.

Key issues identified:

1. Insufficient bounds checking during DICOM field parsing
2. Use of unsafe string functions like strcpy() without length validation
3. Lack of input sanitization for DICOM data fields
4. Missing stack protection mechanisms

A proper patch should include:

1. Input validation to check DICOM field sizes before processing
2. Safe string functions replacement (strncpy, strlcpy)
3. Stack canaries and other memory protection mechanisms
4. Fuzzing and testing of DICOM parsing routines

Attack Surface

Affected Versions:

• MedDream PACS Server: Specific version information under investigation
• Healthcare networks: Using vulnerable DICOM processing systems
• Estimated affected installations: Thousands of healthcare facilities globally

Red Team Perspective

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Initial Access:
  - T1566.001: Phishing: Spearphishing Attachment
  - T1190: Exploit Public-Facing Application

Execution:
  - T1055: Process Injection
  - T1203: Exploitation for Client Execution

Collection:
  - T1005: Data from Local System
  - T1039: Data from Network Shared Drive
  - T1213.003: Data from Information Repositories: Code Repositories

Impact:
  - T1486: Data Encrypted for Impact
  - T1491.001: Internal Defacement

Blue Team Perspective

Historical Context: How Does This Compare?

CVE-2025-3481 fits into a concerning pattern of healthcare infrastructure vulnerabilities:

• WannaCry Healthcare Impact (2017): Demonstrated the catastrophic effect of ransomware on healthcare systems. CVE-2025-3481 provides a potential entry vector for similar attacks through PACS systems.

• Philips Vue PACS Vulnerabilities (2022): Similar healthcare imaging system vulnerabilities affecting patient data. CVE-2025-3481 continues the trend of critical security flaws in medical imaging infrastructure.

• Universal Health Services Attack (2020): Showed how ransomware can paralyze healthcare operations. This vulnerability could enable similar attacks through PACS system compromise.

This vulnerability highlights the critical importance of securing healthcare IT infrastructure, where compromise can directly impact patient care and safety.

Proof of Concept & Intelligence

Intelligence Note: This vulnerability was reported through the Zero Day Initiative (ZDI-CAN-25827) and represents a significant risk to healthcare infrastructure. Organizations should prioritize protective measures while awaiting vendor patches.

Vulnerability Timeline

Action Items & Recommendations

For Security Teams

IMMEDIATE PRIORITY ACTIONS

1. Network isolation of MedDream PACS systems until patches available
2. DICOM file validation and content filtering implementation
3. Healthcare incident response preparation and team notification
4. Patient data backup verification and integrity checking

For Organizations

Organizational Security Measures:

1. Healthcare asset inventory including all PACS systems
2. Network segmentation for medical imaging infrastructure
3. HIPAA compliance review and breach notification procedures
4. Business continuity planning for PACS system outages
5. Vendor communication regarding patch availability and timeline

Key Takeaways

• For Healthcare IT: This vulnerability affects critical patient care infrastructure. Implement immediate protective measures while awaiting vendor patches.
• For Security Teams: Healthcare environments require specialized security approaches. Develop detection capabilities for medical device and DICOM traffic anomalies.
• For Healthcare Executives: PACS system vulnerabilities can impact patient care and HIPAA compliance. Ensure robust incident response and business continuity planning.
• For Compliance Officers: This vulnerability may trigger breach notification requirements. Review HIPAA compliance procedures and documentation requirements.

Additional Resources

Official References

• Zero Day Initiative Advisory ZDI-25-245
• CVE-2025-3481 Details
• DICOM Security Guidelines

Security Frameworks

• MITRE ATT&CK for Healthcare
• NIST Healthcare Cybersecurity Framework
• HHS Healthcare Cybersecurity Guidelines

Learning Resources

• Healthcare Cybersecurity Best Practices
• DICOM Security Implementation Guide
• Buffer Overflow Prevention Techniques

Disclaimer

This analysis is for educational and defensive cybersecurity purposes only. CVE Hub does not condone malicious use of security vulnerabilities. Always ensure proper authorization before testing any security vulnerabilities in production environments. The techniques described here should only be used for legitimate security research, penetration testing, and defense improvement activities.

Note on Content Generation: This CVE analysis and its accompanying banner image have been generated using an automated pipeline that combines security research data with AI-assisted content creation. While we strive for accuracy, readers should verify critical information with official sources and vendor advisories.

Healthcare organizations must prioritize patient safety and data protection while implementing security measures.

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