CVE-2024-5176

Executive Summary

CVE-2024-5176 identifies a critical security vulnerability in Baxter's Welch Allyn Configuration Tool, versions 1.9.4.1 and prior. The flaw is categorized as "Insufficiently Protected Credentials" (CWE-522), meaning the application stores or transmits sensitive authentication data (e.g., passwords, API keys) in a manner that is easily accessible or decipherable. This weakness could allow an attacker who has already obtained stolen credentials to remotely interact with the service, potentially leading to unauthorized access, data exfiltration, or lateral movement within a healthcare network. The vulnerability is particularly concerning in the medical device ecosystem, where compromised credentials could be used to alter device configurations, disrupt patient monitoring, or pivot to other critical systems. No public proof-of-concept (PoC) or exploit code has been released, and the vendor has not yet provided a patch.

Supply Chain & Package Security

This vulnerability is not related to an open-source package (NPM, PyPI, Go, Ruby). It affects a proprietary medical device configuration tool from Baxter/Welch Allyn. The risk is primarily in the healthcare supply chain, where the tool may be distributed via internal networks or third-party integrators. Organizations should verify the integrity of their software distribution channels and ensure that only authorized versions of the tool are deployed.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, which is unusual and likely indicates that the score has not been officially assigned or was omitted. Based on the description and CWE-522, a reasonable estimated CVSS v3.1 vector would be:

Estimated CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

• Attack Vector (AV): Network – The vulnerability can be exploited remotely.
• Attack Complexity (AC): Low – No special conditions are required.
• Privileges Required (PR): Low – The attacker needs valid credentials (stolen).
• User Interaction (UI): None – No user action is needed.
• Scope (S): Unchanged – The exploit does not affect other components.
• Confidentiality (C): High – Credentials can be used to access sensitive data.
• Integrity (I): High – Device configurations could be altered.
• Availability (A): None – The vulnerability does not directly impact availability.

Estimated Base Score: 8.1 (High)

Threat Level: High. The combination of network exploitability, low complexity, and high impact on confidentiality and integrity makes this a serious risk for healthcare environments.

Deep Dive & Mechanics

The vulnerability stems from the Welch Allyn Configuration Tool's handling of credentials. The tool likely stores authentication tokens, passwords, or API keys in a weakly protected format (e.g., plaintext, reversible encryption, or hardcoded in configuration files). An attacker who gains access to these stored credentials (via a previous breach, phishing, or insider threat) can then use them to authenticate to the remote service as a legitimate user.

Attack Flow:

1. Initial Access: The attacker obtains credentials through a separate attack vector (e.g., phishing, data breach, or malware on an admin workstation).
2. Credential Extraction: The attacker uses the Configuration Tool's stored credentials (e.g., from a local database, registry, or config file) to gain valid authentication tokens.
3. Remote Exploitation: With the stolen credentials, the attacker connects to the remote service (likely a Welch Allyn device or management server) and performs actions such as:
   • Changing device settings (e.g., alarm thresholds, network parameters).
   • Exfiltrating patient data or device logs.
   • Disabling security controls.
   • Establishing persistence for future access.

The vulnerability is classified as "Insufficiently Protected Credentials" (CWE-522), which includes scenarios like:

• Storing passwords in plaintext in a configuration file.
• Using reversible encryption (e.g., base64, XOR) instead of hashing.
• Embedding credentials in source code or binaries.
• Transmitting credentials over unencrypted channels.

Vulnerable vs. Patched Code

Since no patch is available, a direct code comparison is not possible. However, based on the CWE, the vulnerable code likely resembles:

Vulnerable (C#/Python example):

// Storing credentials in plaintext
string username = "admin";
string password = "P@ssw0rd";
File.WriteAllText("config.dat", $"{username}:{password}");

Patched (Expected):

// Using secure storage (e.g., Windows Credential Manager or hashing)
SecureString password = new SecureString();
// ... populate from user input
CredentialManager.WriteCredential("WelchAllynService", username, password);

Vulnerable (Python example):

# Hardcoded credentials in source
USERNAME = "admin"
PASSWORD = "secret123"

Patched (Expected):

# Using environment variables or a secrets manager
import os
USERNAME = os.environ.get("WELCH_USER")
PASSWORD = os.environ.get("WELCH_PASS")

Exploitation & Lab Setup

Red Team (Offensive)

Lab Environment:

• Target: Windows 10/11 VM with Welch Allyn Configuration Tool v1.9.4.1 installed.
• Attacker: Kali Linux VM on the same network.
• Network: Isolated lab network with a simulated Welch Allyn device (e.g., using a Python script that mimics the remote service).

Steps:

1. Reconnaissance: Scan the target for open ports (e.g., 443, 8443) and identify the Configuration Tool's service.
2. Credential Harvesting: If you have local access (e.g., via phishing), extract credentials from the tool's storage:
   • Check %APPDATA%\WelchAllyn\config.ini or similar.
   • Use tools like strings or ProcDump to find plaintext passwords.
3. Remote Exploitation: Use the stolen credentials to authenticate to the remote service:

   curl -k -X POST https://target-device:8443/api/login -d "username=admin&password=stolen_pass"
   

4. Post-Exploitation: Once authenticated, modify device settings or exfiltrate data:

   curl -k -X GET https://target-device:8443/api/patients -H "Authorization: Bearer <token>"
   

Blue Team (Defensive)

Detection & Response:

• Monitor for unusual authentication attempts to Welch Allyn devices (e.g., from unexpected IPs or at odd hours).
• Enable logging on the Configuration Tool and the remote service.
• Use endpoint detection and response (EDR) to alert on credential dumping tools (e.g., Mimikatz, ProcDump).
• Implement network segmentation to isolate medical devices from general IT systems.

Honeypot Setup:

• Deploy a fake Welch Allyn device that logs all connection attempts and credentials used.
• Use a Python script to simulate the service:

  from flask import Flask, request
  app = Flask(__name__)
  @app.route('/api/login', methods=['POST'])
  def login():
      print(f"Login attempt: {request.form}")
      return {"error": "Invalid credentials"}, 401
  app.run(host='0.0.0.0', port=8443, ssl_context='adhoc')
  

Indicators of Compromise (IOCs)

Network IOCs:

• Unusual outbound connections from the Configuration Tool to unknown IPs on ports 443, 8443, or 8080.
• Repeated failed login attempts followed by a successful login from a new IP.
• HTTP POST requests to /api/login with credentials in plaintext.

Host IOCs:

• Presence of credential dumping tools (e.g., mimikatz.exe, procdump.exe).
• Modified configuration files in %APPDATA%\WelchAllyn\ or C:\ProgramData\WelchAllyn\.
• Unexpected processes running as WelchAllynConfigTool.exe with network connections.

File IOCs:

• Hash of vulnerable binary: sha256: <unknown>
• Suspicious files named config.ini, credentials.dat, or passwords.txt.

Detection Engineering

YARA Rule

rule CVE_2024_5176_WelchAllyn_Credentials {
    meta:
        description = "Detects plaintext credential storage in Welch Allyn Configuration Tool"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-5176"
    strings:
        $cred1 = "password=" ascii wide nocase
        $cred2 = "username=" ascii wide nocase
        $cred3 = "secret=" ascii wide nocase
        $cred4 = "api_key=" ascii wide nocase
        $tool = "WelchAllyn" ascii wide nocase
    condition:
        $tool and any of ($cred*)
}

Sigma Rule

title: Suspicious Credential Access via Welch Allyn Configuration Tool
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects attempts to extract credentials from Welch Allyn Configuration Tool
author: Valters IT
date: 2025-04-10
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\WelchAllynConfigTool.exe'
        CommandLine|contains:
            - '--dump'
            - '--export'
            - 'config.ini'
            - 'credentials'
    condition: selection
falsepositives:
    - Legitimate administrative use
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET 443,8443 (msg:"CVE-2024-5176 Welch Allyn Credential Exfiltration"; flow:to_server,established; content:"POST"; http_method; content:"/api/login"; http_uri; content:"password="; http_client_body; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate Affected Systems: Disconnect Welch Allyn Configuration Tool from the network if not in use.
2. Change All Credentials: Reset passwords for any accounts that may have been stored by the tool.
3. Monitor Logs: Review authentication logs for the remote service for signs of compromise.

Long-Term Fixes:

• Vendor Patch: Await an official patch from Baxter that implements secure credential storage (e.g., using Windows Credential Manager or a hardware security module).
• Workaround: If patching is not possible, consider using a network firewall to restrict access to the remote service to only authorized IPs.
• Configuration Hardening: Remove any hardcoded credentials from configuration files and use environment variables or a secrets manager.

Compensating Controls:

• Implement multi-factor authentication (MFA) for the remote service.
• Use a privileged access management (PAM) solution to rotate credentials frequently.
• Deploy endpoint detection and response (EDR) to alert on credential dumping.

Valters IT
Securing Healthcare, One Vulnerability at a Time