How to remediate – Arkoon Appliance Detection

1. Introduction

The Arkoon Appliance Detection vulnerability identifies systems running Arkoon security appliances that expose identifying TCP ports. This information can assist attackers in targeting specific devices, potentially leading to focused attacks or altered attack strategies. Firewalls and network monitoring systems are typically affected. A successful exploit could lead to loss of confidentiality through targeted reconnaissance.

2. Technical Explanation

The vulnerability stems from the default open TCP ports associated with Arkoon appliances: 822 (SSH), 1750 (Arkoon Manager), and 1751 (Arkoon Monitoring). Attackers can scan networks for these open ports to identify the presence of an Arkoon appliance. While not a direct exploit, this information reduces the attack surface by revealing specific targets. There is no CVE associated with this detection; it’s a configuration issue rather than a software flaw. An attacker could use Nmap or similar tools to scan a network and identify hosts responding on these ports, indicating an Arkoon appliance presence.

• Root cause: Default open TCP ports on the Arkoon appliance expose its identity.
• Exploit mechanism: Attackers scan networks for specific TCP ports (822, 1750, 1751) to identify Arkoon appliances.
• Scope: Arkoon security dedicated appliances.

3. Detection and Assessment

You can confirm the vulnerability by checking open ports on your firewall or network devices. A quick check involves using a port scanner, while thorough assessment requires reviewing firewall rules and network traffic logs.

• Quick checks: Use `netstat -tulnp` (Linux) or `Get-NetTCPConnection` (PowerShell) to list listening ports on the appliance.
• Scanning: Nmap can be used with a script like `nmap -p 822,1750,1751 ` to identify open Arkoon ports. This is an example only.
• Logs and evidence: Review firewall logs for connections to TCP ports 822, 1750, and 1751 from unauthorized sources.

netstat -tulnp | grep "822|1750|1751"

4. Solution / Remediation Steps

To fix this issue, restrict connections to the firewall itself and allow only trusted sources access. Implement Access Control Lists (ACLs) on your router or firewall to block unauthorized connections to these ports.

4.1 Preparation

• Ensure you have a rollback plan in case of connectivity issues. The previous configuration backup serves as this plan.
• A change window may be required depending on network criticality and impact assessment. Approval from the security team is recommended.

4.2 Implementation

1. Step 1: Configure your firewall to only allow connections to TCP ports 822, 1750, and 1751 from trusted IP addresses or networks.
2. Step 2: If using a router with packet filtering capabilities, add ACL rules that deny connections to these ports from unauthorized systems.
3. Step 3: Verify the new firewall rules are active and functioning as expected.

4.3 Config or Code Example

Before

#Example firewall rule - allowing all traffic on ports 822, 1750, 1751
iptables -A INPUT -p tcp --dport 822 -j ACCEPT
iptables -A INPUT -p tcp --dport 1750 -j ACCEPT
iptables -A INPUT -p tcp --dport 1751 -j ACCEPT

After

#Example firewall rule - allowing only trusted IP on ports 822, 1750, 1751
iptables -A INPUT -s /32 -p tcp --dport 822 -j ACCEPT
iptables -A INPUT -s /32 -p tcp --dport 1750 -j ACCEPT
iptables -A INPUT -s /32 -p tcp --dport 1751 -j ACCEPT

4.4 Security Practices Relevant to This Vulnerability

Several security practices can help mitigate this vulnerability type. Least privilege reduces the impact of exposure, while network segmentation limits the blast radius of attacks.

• Practice 1: Implement least privilege access controls to restrict unnecessary connections and reduce potential attack surfaces.
• Practice 2: Network segmentation isolates critical systems from less trusted networks, limiting the spread of compromise if an appliance is targeted.

4.5 Automation (Optional)

If using infrastructure-as-code, you can automate firewall rule updates to enforce these restrictions.

#Example Ansible playbook snippet
- name: Block unauthorized access to Arkoon ports
  iptables:
    chain: INPUT
    protocol: tcp
    destination_port: "{{ item }}"
    jump: DROP
  loop: [822, 1750, 1751]

5. Verification / Validation

Confirm the fix by verifying that unauthorized connections to ports 822, 1750, and 1751 are blocked. Re-run the earlier detection methods to confirm the issue is resolved. Perform a basic service smoke test to ensure functionality remains intact.

• Post-fix check: Use `netstat -tulnp` (Linux) or `Get-NetTCPConnection` (PowerShell) and verify that only trusted IPs can connect on ports 822, 1750, and 1751.
• Re-test: Run Nmap again with the same script as before (`nmap -p 822,1750,1751 `) and confirm that no ports are open from untrusted sources.
• Smoke test: Verify SSH access to the appliance is still functional from authorized systems.
• Monitoring: Monitor firewall logs for any blocked connection attempts on these ports from unknown IP addresses.

netstat -tulnp | grep "822|1750|1751" #Should show only trusted IPs connected

6. Preventive Measures and Monitoring

Update your security baselines to include restrictions on Arkoon appliance ports. Implement checks in CI/CD pipelines to prevent the deployment of configurations with open, unnecessary ports. Establish a regular patch and configuration review cycle to identify and address potential vulnerabilities promptly.

• Baselines: Update your firewall baseline or security policy to explicitly deny connections to TCP ports 822, 1750, and 1751 from untrusted sources.
• Pipelines: Add static analysis checks in CI/CD pipelines to scan for open ports in infrastructure-as-code configurations.
• Asset and patch process: Implement a regular configuration review cycle (e.g., quarterly) to ensure firewall rules remain aligned with security policies.

7. Risks, Side Effects, and Roll Back

Incorrectly configured firewall rules could block legitimate access to the appliance. Always test changes in a non-production environment first. To roll back, restore your previous firewall configuration backup.

• Risk or side effect 1: Blocking legitimate SSH access if trusted IP addresses are incorrectly configured. Mitigation: Carefully review and test all firewall rules before