Risk Mitigation with BIND9 and PDNS-APP

Our protective DNS resolution platform combines BIND9 with the multi-tenant PDNS-APP panel, allowing ISPs, enterprises, and public organizations to mitigate risks at multiple levels. It is designed to align with the NIST Cybersecurity Framework (CSF) and addresses the five core functions: Identify, Protect, Detect, Respond, and Recover.

🧭 1. Identify

Asset-aware and customer-segmented policies

  • PDNS-APP allows complete segmentation by customer or tenant, associating specific networks (for example, CIDR ranges or DoH tokens) with DNS policy zones (RPZ).

  • Each customer, ISP, or defined network can configure its own blocklists, allowlists, and redirection policies, ensuring operational isolation and granular control.

Mitigated risks:

  • Flat or misconfigured DNS policies that unnecessarily expose users.

  • Inability to trace queries or apply specific controls per network or customer.

🛡 2. Protect

DNS threat blocking, enforced SafeSearch, and resolver hardening

  • Response Policy Zones (RPZ) allow the application of policies based on real-time threat intelligence: malware, phishing, C2 domains, DGA, and newly registered domains (NRD). NXDOMAIN responses can be enforced, queries can be redirected with CNAMEs, or simply dropped (DROP).

  • SafeSearch is enforced on Google, YouTube, and Bing through controlled DNS redirections, ensuring compliance with content policies.

  • Encrypted DNS is supported through DoT (DNS over TLS), DoH (DNS over HTTPS), and DoQ (DNS over QUIC), reducing the risk of interception or manipulation.

Mitigated risks:

  • Access to malicious, inappropriate, or unauthorized content.

  • DNS spoofing or interception attacks (Man-in-the-Middle).

  • Non-compliance with regulations (for example, the mandatory MinTIC list in Colombia).

🔍 3. Detect

Logging, analysis, and anomaly detection in DNS traffic

  • All DNS traffic is logged using dnstap or querylog, and can be exported in real time to platforms such as ClickHouse, Wazuh, ELK, or Kafka.

  • However, most of this information is available directly within the PDNS-APP panel, which provides immediate visibility by RPZ zone, domain, customer, or source IP.

  • The logs include enriched metadata: - Queried domain - RPZ zone that triggered the policy - Applied policy (NXDOMAIN, CNAME, DROP) - Source IP, query type (A, AAAA, etc.)

  • Kafka can be used for real-time analysis of anomalous behavior, including: - DNS tunneling - Malware beaconing - Suspicious activity from algorithmically generated domains (DGA)

Mitigated risks:

  • Blind spots in internal or outbound DNS traffic.

  • Lack of traceability for investigations or audits.

  • Malicious activity not detected by traditional solutions.

  • Exclusive dependence on the SOC: the PDNS-APP panel acts as the first line of DNS monitoring.

🧯 4. Respond

Continuous policy updates and SOC integration

  • Every 2 minutes, PDNS-APP automatically updates RPZ zones using SHA256 comparisons to avoid unnecessary reloads, and executes rndc reload only when required.

  • RPZ events (blocks, redirections) and resolver telemetry are exported via SNMP or syslog, and are also displayed in real time from the panel.

  • The platform integrates with incident response tools such as TheHive, Cortex, or Wazuh, enabling automated corrective actions.

Mitigated risks:

  • Delays in applying blocks against emerging threats.

  • High MTTR (mean time to recovery) due to lack of automation.

  • Lack of operational visibility into DNS-layer events.

♻️ 5. Recover

Resilient architecture and policy version control

  • Resolvers can be deployed in on-premise mode or in controlled regional clouds (for example, in Miami for Latin American ISPs), with backup configurations and automatic watchdogs.

  • RPZ zones and configuration files are version-controlled, allowing secure auditing, restoration, and rollback.

  • The multi-tenant design of PDNS-APP guarantees isolation between customers, limiting the impact of any error or incident.

Mitigated risks:

  • Service failures due to dependence on centralized resolvers.

  • Misapplied policies affecting multiple customers.

  • Regulatory non-compliance due to lack of notices, blocking pages, or traceability.

✅ Supported Security Controls (NIST SP 800-53)

Our solution actively implements security controls defined by the NIST SP 800-53 framework, which are essential for compliance with NIST CSF, FedRAMP, and FISMA:

Supported Security Controls (NIST SP 800-53)

NIST Control

Implemented Mitigation

AC-4 – Information Flow Enforcement

RPZs restrict the flow of DNS information according to customized policies per customer or network.

AU-2 / AU-12 – Audit Events & Generation

All DNS queries are logged and correlated with RPZ events, providing full traceability.

SC-20 / SC-21 – Secure Name Resolution

Full support for DNSSEC validation, enforced SafeSearch, and strict RPZ enforcement.

SI-3 / SI-4 – Malicious Code / Monitoring

Threat feed ingestion + detection of beaconing, DGA, or C2 activities through logs and Kafka.

IR-4 – Incident Handling

Automatic list updates every 2 minutes and direct integration with SOC tools (Wazuh, TheHive, etc.).