CVE-2025-0574

Executive Summary

CVE-2025-0574 is a critical memory corruption vulnerability in the Sante PACS Server web server module, allowing unauthenticated remote attackers to cause a denial-of-service (DoS) condition. The flaw stems from improper validation of user-supplied URL data, leading to memory corruption. With a CVSS score of 8.2, this vulnerability poses a significant risk to healthcare imaging systems, potentially disrupting PACS operations. No public proof-of-concept (PoC) or patch is currently available, but the vulnerability has been reported via ZDI-CAN-25318.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects a proprietary medical imaging server (Sante PACS Server), which is typically deployed in on-premises healthcare environments. Supply chain risks include unpatched third-party libraries used by the server, but no specific package details are available.

CVSS Breakdown & Threat Level

• CVSS Score: 8.2 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: None (C:N)
• Integrity Impact: None (I:N)
• Availability Impact: High (A:H)

Threat Level: High. The vulnerability is remotely exploitable without authentication, making it attractive for attackers targeting healthcare infrastructure. The lack of a patch increases risk.

Deep Dive & Mechanics

The vulnerability exists in the web server module of Sante PACS Server, specifically during URL parsing. The server fails to properly validate the length or content of incoming URL strings, leading to a memory corruption condition (likely a buffer overflow or out-of-bounds write). When a specially crafted URL is sent, the server writes beyond allocated memory, corrupting critical data structures and causing the process to crash or become unresponsive.

Root Cause: Insufficient bounds checking on URL input before copying into fixed-size buffers. This is a classic CWE-787 (Out-of-bounds Write) vulnerability.

Attack Vector: An attacker sends a malicious HTTP request with an overly long or malformed URL to the Sante PACS Server's web interface (typically port 80 or 443). The server processes the URL without validation, triggering memory corruption.

Impact: Successful exploitation results in a denial-of-service condition, rendering the PACS server unavailable. This can disrupt medical image storage, retrieval, and viewing, potentially impacting patient care.

Vulnerable vs. Patched Code

Since no patch is available, a hypothetical vulnerable code snippet is provided for illustration.

Vulnerable Code (C-style pseudocode):

void handle_request(char *url) {
    char buffer[256];
    // No bounds check - vulnerable to overflow
    strcpy(buffer, url);
    // Process buffer...
}

Patched Code (Hypothetical):

void handle_request(char *url) {
    char buffer[256];
    // Proper bounds checking
    if (strlen(url) >= sizeof(buffer)) {
        // Reject request or truncate
        return;
    }
    strcpy(buffer, url);
    // Process buffer...
}

The patched version validates the length of the URL before copying, preventing memory corruption.

Exploitation & Lab Setup

Red Team (Attacker)

Objective: Cause a denial-of-service on Sante PACS Server.

Lab Setup:

• Target: Sante PACS Server (vulnerable version) running on a local VM (e.g., Windows Server 2019).
• Attacker: Kali Linux or any system with netcat/curl.

Exploitation Steps:

1. Identify the target IP and port (default 80).
2. Craft a malicious URL with a long string (e.g., 1000 'A' characters).
3. Send the request using curl:

   curl -v "http://<target_ip>:80/$(python3 -c 'print("A"*1000)')"
   

4. Monitor the server: The service should crash or become unresponsive.

Note: No public exploit code is available. The above is a conceptual demonstration.

Blue Team (Defender)

Detection:

• Monitor for HTTP requests with abnormally long URLs (e.g., > 1024 bytes).
• Use network intrusion detection systems (NIDS) to alert on suspicious patterns.
• Enable logging on the Sante PACS Server and review web server logs for malformed requests.

Mitigation:

• If possible, restrict network access to the PACS server using firewalls.
• Implement a web application firewall (WAF) to filter oversized URLs.
• Monitor for crashes or service restarts in the PACS server.

Indicators of Compromise (IOCs)

• Network:
  • HTTP requests with URLs exceeding 1024 bytes.
  • Repeated connection attempts to port 80/443 of the Sante PACS Server.
• Host:
  • Sante PACS Server process crash logs (e.g., Event ID 1000 on Windows).
  • Memory dumps indicating buffer overflow.
• Logs:
  • Web server logs showing malformed URLs (e.g., long strings of 'A' characters).

Detection Engineering

YARA Rule

rule CVE_2025_0574_Sante_PACS_DOS {
    meta:
        description = "Detects memory corruption attempts against Sante PACS Server via long URLs"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-0574"
    strings:
        $long_url = /GET \/[A-Za-z0-9]{500,} HTTP/
    condition:
        $long_url
}

Sigma Rule

title: Sante PACS Server Long URL DoS Attempt
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects HTTP requests with abnormally long URLs targeting Sante PACS Server
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: sante_pacs
detection:
    selection:
        cs-uri-stem|length: >= 1024
    condition: selection
falsepositives:
    - Legitimate long URLs (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-0574 Sante PACS Server Long URL DoS Attempt"; flow:to_server; content:"GET"; http_method; urilen:>1024; classtype:attempted-dos; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the PACS Server: Restrict network access to only trusted IPs using firewalls.
2. Deploy WAF: Use a web application firewall to block requests with URLs longer than 1024 bytes.
3. Monitor Logs: Enable detailed logging and alert on long URLs or server crashes.

Long-term Fix:

• Contact Sante for a patch or update. Since no patch is available, consider upgrading to a newer version if released.
• Implement input validation in any custom web interfaces.

Workaround:

• If the web server module is not essential, disable it or restrict access to localhost only.

Valters IT