DNS Evidence You Don’t Know What You’re Missing

Step-by-Step Tutorial: Analyzing DNS Evidence

1. Introduction to DNS Evidence:

   • DNS evidence has been in use for a long time and is becoming increasingly important in various use cases and methods for collection.
   • DNS provides valuable insights into establishing services, authorizations, and abnormal activities within an environment.

2. Passive DNS Collection:

   • Passive DNS involves collecting historical DNS data sets containing DNS queries and responses for incident response or hunting purposes.
   • Methods for collecting passive DNS data include using pcap, endpoint tools, or proxy systems to store and analyze DNS activities.

3. Analyzing Passive DNS Records:

   • Passive DNS records contain standardized data points such as timestamps, client IP addresses, server responses, queried names, record types, TTL values, and the number of records.
   • Analyzing passive DNS records helps in identifying abnormal activities, establishing command and control connections, and detecting malicious domains.

4. Utilizing Passive DNS for Investigations:

   • Passive DNS records can be leveraged to investigate fast flux architectures, phased C2 operations, and NX domain entries to detect suspicious or malicious activities.
   • Historical passive DNS data provides critical insights into changes in resolved IP addresses, TTL values, and suspicious domain resolutions over time.

5. Tools for DNS Analysis:

   • Tools like tcpdump, Wireshark, and custom parsers can be used to capture and analyze DNS traffic for forensic investigations.
   • Utilizing open-source threat intelligence sources like Emerging Threats, DShield, and DNSDB enhances the visibility and detection of malicious domains.

6. Enhancing DNS Security:

   • Implementing DNSSEC for authoritative DNS servers can improve authentication and security for DNS queries and responses.
   • Regularly monitoring DNS activities, analyzing passive DNS records, and leveraging threat intelligence sources are crucial for enhancing DNS security.

7. Conclusion:

   • DNS evidence plays a vital role in incident response, threat hunting, and network forensics by providing valuable insights into domain resolutions, command and control activities, and malicious behaviors.
   • Continuous monitoring of DNS activities, historical analysis of passive DNS records, and collaboration with threat intelligence sources are essential for improving DNS security and detecting malicious activities.

By following these steps, you can effectively analyze DNS evidence, identify suspicious activities, and enhance the security of your network infrastructure.