DNS sits at the foundation of internet connectivity, yet most organisations treat it as an afterthought in their security strategies. That oversight creates serious vulnerabilities.
The Domain Name System translates human-readable domain names into IP addresses. This fundamental service handles billions of queries every day. Its ubiquity makes it an attractive target for attackers.
DNS poisoning attacks corrupt the resolution process, directing users to malicious servers instead of legitimate destinations. Users believe they’re visiting their bank’s website or accessing company resources. In reality, they’re handing credentials directly to attackers.
Detection proves challenging because DNS operates at such a fundamental level. Compromised DNS entries can redirect traffic for days or weeks before anyone notices. Meanwhile, attackers harvest credentials, inject malware, and steal sensitive data. Comprehensive external network penetration testing examines how attackers might exploit DNS to gain initial access or facilitate attacks against your organisation.
DNS tunnelling exploits the protocol for command and control communications. Attackers encode data within DNS queries and responses, bypassing firewalls and security controls that often overlook DNS traffic. Malware beacons home, receives instructions, and exfiltrates data, all through DNS queries that appear normal.
William Fieldhouse, Director of Aardwolf Security Ltd, explains: “DNS rarely features prominently in security assessments, yet it represents a critical attack vector. When we conduct thorough network penetration testing, DNS misconfigurations and vulnerabilities frequently provide paths to deeper compromise.”
DDoS attacks targeting DNS infrastructure can bring entire organisations offline. If your authoritative DNS servers go down, nobody can reach your services, regardless of how robust your application infrastructure might be. The attack surface extends to your DNS hosting provider as well.
DNSSEC provides cryptographic authentication of DNS responses. It ensures that the response you receive actually came from the authoritative DNS server and hasn’t been modified in transit. Implementation requires careful configuration, but it eliminates entire classes of attacks.
Many organisations still run outdated DNS server software with known vulnerabilities. These systems process untrusted data from the internet continuously. Exploiting vulnerabilities in DNS servers can grant attackers control of a critical piece of infrastructure.
DNS over HTTPS (DoH) and DNS over TLS (DoT) encrypt DNS queries, preventing eavesdropping and manipulation. Traditional DNS queries travel in plain text, allowing anyone on the network path to observe your browsing patterns and potentially inject malicious responses.
Monitoring DNS traffic reveals valuable threat intelligence. Unusual query patterns, requests for suspicious domains, or anomalous response behaviour often indicate compromised systems. DNS monitoring should integrate with your broader security information and event management strategy. Working with the best penetration testing company ensures a comprehensive evaluation of your DNS security posture.
Split DNS configurations separate internal and external name resolution, limiting information disclosure. External DNS servers should reveal only what absolutely must be public. Internal DNS contains detailed information about your infrastructure topology but remains inaccessible from outside.