Healthcare Data Breach at Southern Illinois Ob-Gyn Associates: Defense and Incident Response Strategies

---
title: Suspicious Access to Patient Database
id: 68a93d47-2f18-4e9b-9c7a-8d3b6e5c4f1a
status: experimental
description: Detects unusual access patterns to patient database files or systems
references:
  - https://attack.mitre.org/techniques/T1083/
  - https://attack.mitre.org/techniques/T1005/
author: Security Arsenal
date: 2026/04/10
tags:
  - attack.collection
  - attack.t1083
  - attack.t1005
logsource:
  category: file_access
  product: windows
detection:
  selection:
    TargetFilename|contains:
      - 'patient'
      - 'medical_records'
      - 'phi'
      - 'ehr'
      - 'emr'
      - 'epic'
      - 'cerner'
      - 'allscripts'
  condition: selection | count(TargetFilename) > 100
falsepositives:
  - Legitimate healthcare administrative activities
  - System backups
level: high
---
title: Unusual EHR System Data Export
id: 8d3c1b52-7a9e-4f5d-8c1b-2d3e4f5a6b7c
status: experimental
description: Detects potential data exfiltration from Electronic Health Record systems
references:
  - https://attack.mitre.org/techniques/T1041/
  - https://attack.mitre.org/techniques/T1567/
author: Security Arsenal
date: 2026/04/10
tags:
  - attack.exfiltration
  - attack.t1041
  - attack.t1567
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith:
      - '\sqlcmd.exe'
      - '\bcp.exe'
      - '\mysql.exe'
      - '\pg_dump.exe'
      - '\exp.exe'
      - '\dtsrun.exe'
    CommandLine|contains:
      - 'output'
      - 'queryout'
      - 'export'
      - 'dump'
      - 'extract'
  filter:
    User|contains:
      - 'svc_'
      - 'admin'
      - 'db_'
  condition: selection and not filter
falsepositives:
  - Authorized database exports by administrators
  - Scheduled backup tasks
level: high
---
title: Healthcare Ransomware Behavior
id: 3b5d8c2a-1f9e-4d7a-8c3b-2d4e5f6a7b8c
status: experimental
description: Detects behaviors consistent with ransomware often targeting healthcare organizations
references:
  - https://attack.mitre.org/techniques/T1486/
  - https://attack.mitre.org/tactics/TA0040/
author: Security Arsenal
date: 2026/04/10
tags:
  - attack.impact
  - attack.t1486
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith:
      - '\vssadmin.exe'
      - '\wbadmin.exe'
      - '\bcdedit.exe'
      - '\powershell.exe'
    CommandLine|contains:
      - 'delete shadows'
      - 'delete backup'
      - 'recoveryenabled no'
      - 'encrypt'
      - 'lock'
  timeframe: 1h
  condition: selection
falsepositives:
  - Legitimate system maintenance
  - Authorized backup management
level: critical

// Detect unusual access to patient data
let baseline = DeviceProcessEvents
| where Timestamp > ago(14d)
| where FileName in~ ("sqlcmd.exe", "bcp.exe", "mysql.exe", "pg_dump.exe", "powershell.exe")
| summarize count() by bin(Timestamp, 1h), AccountName, DeviceName
| summarize AvgCount = avg(count_), MaxCount = max(count_) by AccountName, DeviceName;
DeviceProcessEvents
| where Timestamp > ago(1h)
| where FileName in~ ("sqlcmd.exe", "bcp.exe", "mysql.exe", "pg_dump.exe", "powershell.exe")
| summarize CurrentCount = count() by bin(Timestamp, 1h), AccountName, DeviceName
| join kind=inner baseline on AccountName, DeviceName
| where CurrentCount > MaxCount * 3
| project Timestamp, DeviceName, AccountName, CurrentCount, MaxCount, AvgCount;


// Detect potential data exfiltration to external endpoints
DeviceNetworkEvents
| where Timestamp > ago(24h)
| where ActionType == "ConnectionSuccess"
| where RemotePort in (443, 445, 21, 22, 3389)
| where RemoteUrl !contains ".healthcare.local" // Replace with your organization's domain
| where InitiatingProcessFileName in~ ("powershell.exe", "cmd.exe", "winscp.exe", "filezilla.exe", "putty.exe")
| summarize TotalBytes = sum(SentBytes), ConnectionCount = count() by DeviceName, InitiatingProcessAccountName, RemoteUrl, RemoteIP
| where TotalBytes > 50000000 or ConnectionCount > 100
| project Timestamp, DeviceName, InitiatingProcessAccountName, RemoteUrl, RemoteIP, TotalBytes, ConnectionCount;

-- Hunt for processes accessing sensitive patient data locations
SELECT Pid, Name, CommandLine, Exe, Username, CreateTime
FROM pslist()
WHERE CommandLine =~ 'patient' 
   OR CommandLine =~ 'medical'
   OR CommandLine =~ 'ehr'
   OR CommandLine =~ 'phi'
   OR Exe =~ '\\EHR\\'
   OR Exe =~ '\\MedicalRecords\\'


-- Check for unusual network connections to external endpoints
SELECT Fqdn, RemoteAddress, RemotePort, Pid, ProcessName, StartTime, Uid
FROM netstat()
WHERE State = 'ESTABLISHED'
   AND Fqdn !in array(internal_domains) // Replace with your organization's domains
   AND (RemotePort = 443 OR RemotePort = 445 OR RemotePort = 22 OR RemotePort = 3389)
   AND ProcessName IN ('powershell.exe', 'cmd.exe', 'putty.exe', 'winscp.exe', 'filezilla.exe')

# Healthcare Data Breach Response and Hardening Script
# Run this on potentially affected Windows systems in a healthcare environment

# 1. Check for unauthorized user accounts
Write-Host "Checking for unauthorized user accounts..." -ForegroundColor Yellow
$UnusualUsers = Get-LocalUser | Where-Object {$_.LastLogon -lt (Get-Date).AddDays(-90) -and $_.Enabled -eq $true}
$UnusualUsers | Format-Table Name, LastLogon, Enabled -AutoSize

# 2. Audit group memberships for privileged accounts
Write-Host "Auditing group memberships..." -ForegroundColor Yellow
$AdminGroups = Get-LocalGroup | Where-Object {$_.Name -match "Admin|Administrator"}
foreach ($group in $AdminGroups) {
    Write-Host "Members of $($group.Name):" -ForegroundColor Cyan
    Get-LocalGroupMember -Group $group.Name | Format-Table Name, PrincipalSource -AutoSize
}

# 3. Check for recently modified files in sensitive directories
Write-Host "Checking for recently modified files in sensitive directories..." -ForegroundColor Yellow
$SensitiveDirs = @("C:\PatientData", "C:\MedicalRecords", "C:\EHR", "C:\EMR")
foreach ($dir in $SensitiveDirs) {
    if (Test-Path $dir) {
        Get-ChildItem -Path $dir -Recurse -File | 
        Where-Object {$_.LastWriteTime -gt (Get-Date).AddDays(-7)} |
        Format-Table FullName, LastWriteTime, Length -AutoSize
    }
}

# 4. Check for unusual scheduled tasks
Write-Host "Checking for unusual scheduled tasks..." -ForegroundColor Yellow
$SuspiciousTasks = Get-ScheduledTask | Where-Object {
    $_.State -eq "Ready" -and 
    ($_.TaskName -match "update" -or $_.TaskName -match "backup" -or $_.TaskName -match "maintenance") -and 
    $_.Author -notmatch "Microsoft|System|Administrator"
}
$SuspiciousTasks | Format-List TaskName, Author, LastRunTime, NextRunTime

# 5. Audit RDP access settings
Write-Host "Auditing RDP access settings..." -ForegroundColor Yellow
$RDPStatus = (Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Terminal Server" -Name "fDenyTSConnections").fDenyTSConnections
if ($RDPStatus -eq 0) {
    Write-Host "WARNING: RDP is enabled" -ForegroundColor Red
    $RDPOptions = Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp"
    Write-Host "UserAuthentication: $($RDPOptions.UserAuthentication)"
    Write-Host "SecurityLayer: $($RDPOptions.SecurityLayer)"
} else {
    Write-Host "RDP is disabled (Good)" -ForegroundColor Green
}

# 6. Check for unusual services
Write-Host "Checking for unusual services..." -ForegroundColor Yellow
$SuspiciousServices = Get-Service | Where-Object {
    $_.Status -eq "Running" -and 
    $_.StartType -eq "Automatic" -and
    $_.DisplayName -notmatch "Microsoft|Windows|Healthcare|EHR|EMR|Antivirus|Security"
}
$SuspiciousServices | Format-Table Name, DisplayName, Status, StartType -AutoSize

# 7. Review recent security event logs
Write-Host "Reviewing recent security event logs..." -ForegroundColor Yellow
$RecentEvents = Get-WinEvent -LogName Security -MaxEvents 100 -ErrorAction SilentlyContinue | 
Where-Object {$_.TimeCreated -gt (Get-Date).AddHours(-24)} |
Where-Object {$_.Id -in (4624, 4625, 4720, 4728, 4732, 4756, 4738, 4662)}
$RecentEvents | Format-Table TimeCreated, Id, Message -AutoSize -Wrap

# 8. Harden PowerShell execution policy
Write-Host "Hardening PowerShell execution policy..." -ForegroundColor Yellow
Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope LocalMachine -Force

# 9. Enable Windows Firewall logging
Write-Host "Enabling Windows Firewall logging..." -ForegroundColor Yellow
Set-NetFirewallProfile -Profile Domain,Public,Private -LogAllowed True -LogBlocked True -LogIgnored True

# 10. Generate a report
Write-Host "Generating security report..." -ForegroundColor Yellow
$ReportPath = "C:\SecurityReports\BreachResponse_$(Get-Date -Format 'yyyyMMdd').txt"
$SecurityReport = @"
Healthcare Security Assessment Report
Generated: $(Get-Date)
======================================

Unauthorized User Accounts:
$($UnusualUsers | Out-String)

Scheduled Tasks:
$($SuspiciousTasks | Out-String)

Suspicious Services:
$($SuspiciousServices | Out-String)

RDP Status: $RDPStatus
"@
$SecurityReport | Out-File -FilePath $ReportPath -Encoding UTF8
Write-Host "Report saved to $ReportPath" -ForegroundColor Green