Hardening Access Controls in Healthcare and Manufacturing: Defending Against Credential-Based Attacks

In the modern threat landscape, two of the most critical economic sectors—manufacturing and healthcare—face a shared and persistent vulnerability: weak password hygiene and poor access management. While insiders often view strict access controls as operational roadblocks, malicious actors view them as the primary gateway into sensitive networks.

For security teams, this dichotomy presents a serious challenge. The convergence of Operational Technology (OT) in manufacturing and the high-value data of Electronic Health Records (EHR) makes these sectors prime targets for credential stuffing, brute force attacks, and lateral movement. This post analyzes the mechanics of these threats and provides actionable defensive measures to secure your organization’s identity perimeter.

Technical Analysis

The core issue is not merely weak passwords, but the mismanagement of authentication and authorization mechanisms. In both sectors, legacy systems often coexist with modern IT environments, creating gaps that attackers exploit.

• The Vulnerability: The reliance on static credentials for accessing sensitive systems, including EHR platforms, SCADA systems, and network shares.
• Attack Vector: Attackers commonly use brute force techniques to guess simple passwords or use purchased credentials on the dark web to gain initial access. Once inside, they attempt to dump credentials from memory (LSASS) to elevate privileges and move laterally.
• Affected Systems:
  • Active Directory (AD) and Azure Active Directory (AAD)
  • Electronic Health Record (EHR) applications (e.g., Epic, Cerner)
  • Industrial Control Systems (ICS) and Human Machine Interfaces (HMI)
  • Remote access protocols (RDP, VPN)
• Severity: High. Credential theft is a primary precursor to ransomware deployment in both healthcare and manufacturing.

Defensive Monitoring

To defend against these threats, security operations centers (SOCs) must monitor for signs of brute force activity, credential dumping, and unauthorized user creation. Below are detection rules and queries for your defensive arsenal.

SIGMA Detection Rules

The following SIGMA rules identify potential credential dumping and suspicious user creation activities often seen after an attacker bypasses initial password defenses.

---
title: Potential Credential Dumping via ProcDump
id: 8a1b2c3d-4e5f-6789-0123-456789abcdef
status: experimental
description: Detects the use of ProcDump or similar tools to dump process memory for credential extraction, often occurring after password theft.
references:
  - https://attack.mitre.org/techniques/T1003/
author: Security Arsenal
date: 2023/10/25
tags:
  - attack.credential_access
  - attack.t1003.001
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith: '\procdump.exe'
    CommandLine|contains: 'lsass'
falsepositives:
  - Legitimate debugging by system administrators
level: high
---
title: Local User Creation via Command Line
id: c3d4e5f6-7890-1234-5678-9abcdef01234
status: experimental
description: Detects the creation of a new local user via net.exe or cmd, often a sign of backdoor creation after credential theft.
references:
  - https://attack.mitre.org/techniques/T1136/
author: Security Arsenal
date: 2023/10/25
tags:
  - attack.persistence
  - attack.t1136.001
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith:
      - '\net.exe'
      - '\net1.exe'
    CommandLine|contains: 'user'
    CommandLine|contains:
      - 'add'
      - '/add'
falsepositives:
  - Legitimate administrative user creation
level: high
---
title: Suspicious High Volume Network Connections to SMB Port
id: b2c3d4e5-6f78-9012-3456-789abcdef01
status: experimental
description: Detects network connections to port 445 (SMB) from a single source IP, indicative of brute force or password spraying attempts.
references:
  - https://attack.mitre.org/techniques/T1110/
author: Security Arsenal
date: 2023/10/25
tags:
  - attack.credential_access
  - attack.t1110.001
logsource:
  category: network_connection
  product: windows
detection:
  selection:
    DestinationPort: 445
    Initiated: true
condition: selection
falsepositives:
  - Legitimate file transfer activities
level: medium

KQL Queries (Microsoft Sentinel/Defender)

Use these KQL queries to hunt for failed sign-in attempts indicative of brute force attacks and verify MFA enforcement.

// Hunt for brute force signs - High count of failed logins per IP
SigninLogs
| where ResultType == 50126 // Invalid username or password
| summarize FailedLogins=count() by IPAddress, AppDisplayName
| where FailedLogins > 10
| sort by FailedLogins desc

// Check for users without MFA (Weak Configuration)
AADUserRiskEvents 
| join kind=inner (IdentityInfo) on UserPrincipalName 
| where isnotempty(UserPrincipalName)
| project UserPrincipalName, MFAState = coalesce(PerUserMfaState, "Disabled")
| distinct UserPrincipalName, MFAState
| where MFAState == "Disabled"

Velociraptor VQL Hunt Queries

These VQL hunts help identify potential credential storage files and suspicious process execution on endpoints.

-- Hunt for suspicious files containing 'password' in the filename
SELECT FullPath, Size, Mtime, Atime
FROM glob(globs='C:\Users\*\*.txt', root='/', accessor='auto')
WHERE FullPath =~ '(?i)password' 
   OR FullPath =~ '(?i)credential'

-- Hunt for execution of common credential dumping tools
SELECT Name, CommandLine, Exe, Username, CreateTime
FROM pslist()
WHERE Name =~ 'mimikatz' 
   OR Name =~ 'procdump'
   OR Name =~ 'Rubeus'
   OR CommandLine =~ 'dump'

PowerShell Remediation Script

This script can be used to audit Active Directory for accounts with weak password settings, specifically those with "Password Not Required" set.

# Audit AD Users for 'Password Not Required' flag
Import-Module ActiveDirectory

$WeakAccounts = Search-ADAccount -PasswordNotRequired | `
    Get-ADUser -Properties Name, SamAccountName, Enabled, PasswordNeverExpires, LastLogonDate

if ($WeakAccounts) {
    Write-Warning "Found accounts where password is not required:"
    $WeakAccounts | Format-Table Name, SamAccountName, Enabled, PasswordNeverExpires, LastLogonDate -AutoSize
} else {
    Write-Host "No accounts found with 'Password Not Required' set." -ForegroundColor Green
}

Remediation

To protect your organization against the password struggles plaguing healthcare and manufacturing, implement the following remediation steps immediately:

1. Enforce Multi-Factor Authentication (MFA): This is the single most effective control. Require MFA for all users, especially those accessing remote desktops, VPNs, and EHR systems.
2. Implement Password Policies and Managers: Move away from frequent password changes (which encourage simple patterns) and enforce long passphrases. Deploy an enterprise password manager to reduce the cognitive load on staff.
3. Deploy Privileged Access Management (PAM): Eliminate standing admin rights. Use Just-In-Time (JIT) access for administrative tasks to limit the damage of credential theft.
4. Segment the Network: Ensure that OT and IoT devices in manufacturing are on separate VLANs from the corporate IT network. This prevents lateral movement if a user credential is compromised on the office side.
5. User Education: Train staff specifically on the risks of credential sharing and phishing. Help them understand that security controls are not "roadblocks" but necessary safeguards for patient safety and production continuity.

Related Resources

Security Arsenal Healthcare Cybersecurity AlertMonitor Platform Book a SOC Assessment healthcare Intel Hub