Device trust and endpoint security are critical components of a Zero Trust Architecture (ZTA). The problem arises when you need to ensure that only trusted devices can access your network and data, even if they’re connecting from unsecured locations. In ZTA, you assume all devices are potentially compromised until proven otherwise. This shifts the focus from perimeter defense to continuous verification of every device and user interaction.

Understanding Device Trust

Device trust involves verifying the integrity and compliance of devices before granting them access to your network. This includes checking for operating system updates, installed security software, and adherence to company policies. The goal is to ensure that only healthy, compliant devices can connect to sensitive resources.

Common Mistakes

  1. Overlooking Mobile Devices: Many organizations focus on desktops and laptops while neglecting mobile devices. This is a mistake since mobile devices are increasingly used for work and often have less stringent security controls.
  2. Ignoring OS Updates: Not keeping operating systems and applications updated can leave devices vulnerable to known exploits.
  3. Failing to Monitor Active Sessions: Continuous monitoring of active sessions is crucial to detect and respond to suspicious activities promptly.

Implementing Device Trust

Let’s look at how to set up device trust using an example with Microsoft Intune and Azure AD Conditional Access.

Step 1: Configure Device Compliance Policies

First, define what constitutes a compliant device. This might include having the latest OS version, antivirus software installed, and encryption enabled.

{
    "displayName": "Windows Compliance Policy",
    "description": "Ensures Windows devices meet compliance requirements.",
    "platforms": "windows10AndLater",
    "settings": [
        {
            "@odata.type": "#microsoft.graph.windowsMinimumOperatingSystem",
            "v10_0": true
        },
        {
            "@odata.type": "#microsoft.graph.windowsDeviceHealthAttestationState",
            "osVersion": ">=10.0.17763.0"
        },
        {
            "@odata.type": "#microsoft.graph.deviceComplianceSettingState",
            "setting": "Encryption",
            "state": "compliant"
        }
    ]
}

Step 2: Create Conditional Access Policies

Next, create policies in Azure AD Conditional Access that enforce these compliance requirements.

{
    "displayName": "Require Compliant Devices",
    "state": "enabled",
    "conditions": {
        "applications": {
            "includeApplications": ["All"]
        },
        "users": {
            "includeUsers": ["All"]
        },
        "devices": {
            "deviceStates": ["compliant"]
        }
    },
    "grantControls": {
        "operator": "AND",
        "builtInControls": ["block"]
    }
}

Example of a Device Trust Policy

Here’s a more detailed example of a device trust policy that checks for OS version, antivirus status, and encryption.

{
    "displayName": "Advanced Windows Compliance Policy",
    "description": "Advanced compliance checks for Windows devices.",
    "platforms": "windows10AndLater",
    "settings": [
        {
            "@odata.type": "#microsoft.graph.windowsMinimumOperatingSystem",
            "v10_0": true,
            "v10_0_17763": true
        },
        {
            "@odata.type": "#microsoft.graph.windowsDeviceHealthAttestationState",
            "osVersion": ">=10.0.17763.0",
            "bitLockerEnabled": true,
            "secureBootEnabled": true
        },
        {
            "@odata.type": "#microsoft.graph.deviceThreatProtectionEnabled",
            "isEnabled": true
        }
    ]
}

Endpoint Security

Endpoint security focuses on protecting individual devices from threats such as malware, unauthorized access, and data breaches. This includes antivirus software, firewalls, and regular security audits.

Common Pitfalls

  1. Outdated Software: Failing to keep security software updated can leave devices vulnerable.
  2. Lack of Monitoring: Without continuous monitoring, threats can go undetected for extended periods.
  3. Insufficient User Training: Users can inadvertently introduce threats through phishing attacks or poor security practices.

Setting Up Endpoint Security

Let’s explore how to set up endpoint security using Symantec Endpoint Protection.

Step 1: Install and Configure Antivirus

Install Symantec Endpoint Protection on all endpoints and configure it to scan regularly and update definitions automatically.

# Install Symantec Endpoint Protection
sudo apt-get install symantec-endpoint-protection

# Configure automatic updates
sudo sed -i 's/UpdateFrequency=weekly/UpdateFrequency=daily/g' /etc/symantec/sep/config.ini

Step 2: Enable Firewall Rules

Configure firewall rules to block unauthorized incoming and outgoing traffic.

# Allow SSH access
sudo ufw allow 22/tcp

# Deny all other incoming traffic
sudo ufw default deny incoming

# Enable UFW
sudo ufw enable

Example of Endpoint Security Configuration

Here’s a more comprehensive example of configuring endpoint security with Symantec Endpoint Protection and UFW.

# Install Symantec Endpoint Protection
sudo apt-get update
sudo apt-get install symantec-endpoint-protection

# Configure automatic updates
sudo sed -i 's/UpdateFrequency=weekly/UpdateFrequency=daily/g' /etc/symantec/sep/config.ini

# Enable real-time scanning
sudo sed -i 's/RealTimeScan=disabled/RealTimeScan=enabled/g' /etc/symantec/sep/config.ini

# Configure firewall rules
sudo ufw allow 22/tcp
sudo ufw allow 80/tcp
sudo ufw allow 443/tcp
sudo ufw default deny incoming
sudo ufw default allow outgoing
sudo ufw enable

Security Considerations

  • Keep Software Updated: Regularly update security software to protect against new threats.
  • Monitor Active Sessions: Continuously monitor devices for unusual activity.
  • User Training: Educate users about security best practices and phishing awareness.

Continuous Monitoring

Continuous monitoring is crucial for maintaining device trust and endpoint security. Tools like Splunk, Microsoft Defender for Endpoint, and IBM QRadar can help monitor and analyze security events in real-time.

Example: Using Splunk for Monitoring

# Install Splunk Universal Forwarder
wget -O splunkforwarder-9.0.1-f6a3422747f9-Linux-x86_64.tgz 'https://www.splunk.com/bin/spl/bin/download/forwarder/splunkforwarder-9.0.1-f6a3422747f9-Linux-x86_64.tgz?ac=&wget=true'
tar -xzf splunkforwarder-9.0.1-f6a3422747f9-Linux-x86_64.tgz -C /opt
/opt/splunkforwarder/bin/splunk start --accept-license --answer-yes --no-prompt --seed-passwd 'yourpassword'

# Configure inputs.conf to monitor logs
echo "[monitor:///var/log/auth.log]" >> /opt/splunkforwarder/etc/system/local/inputs.conf
echo "index = main" >> /opt/splunkforwarder/etc/system/local/inputs.conf

# Restart Splunk Forwarder
/opt/splunkforwarder/bin/splunk restart

Conclusion

Implementing device trust and endpoint security in a Zero Trust Architecture requires a proactive approach to ensure that only compliant devices can access your network. By configuring device compliance policies, setting up endpoint security measures, and continuously monitoring devices, you can significantly enhance your organization’s security posture. Get this right and you’ll sleep better knowing your data is protected.

That’s it. Simple, secure, works.