The Domain Name System Security Extensions (DNSSEC) is a suite of Internet Engineering Task Force (IETF).Cyber attacks on Domain Name System (DNS) servers represent one of the most significant threats to Internet security today. Because DNS is used by nearly all networked applications – including email, Web browsing, ecommerce, Internet telephony, and more – these types of attacks threaten the very basis of modern communications and commerce. Whether conducted for financial motives, political gain, or the notoriety of the hacker, the damage from a DNS attack can be devastating for the target organizations.

DNS Security Flaws and Management Challenges

There are several architectural challenges and security flaws inherent in the original design of the DNS protocol for external name servers.

Complex Management

Although most administrators recognize the importance of external name servers,
the occasional misconfiguration or operational mistake is inevitable, largely because of the complexity of managing most name servers. For example, nearly every administrator of a BIND name server—the preferred make of external name server— has made a mistake and introduced a syntax error into a named. Config file or zone data le (a similar risk of human-error is also high when using non-BIND solutions, like Microsoft). However, a syntax error in a zone data le, gone unnoticed, will render the name server unable to load that zone, and will result in a name server returning either old data or no data. Worse, a syntax error in the name server’s configuration le will prevent the name server from starting.

  Attack Vulnerabilities

Many administrators don’t take the simple precaution of configuring their forwarders to process recursive queries only from internal IP addresses. This may be because they don’t know how or because they don’t understand the implications of leaving an external name server “open” to recursive queries.

For example, an inherent vulnerability occurs when a name server allows recursive queries from arbitrary IP addresses. This approach is vulnerable to cache-poisoning attacks, in which a hacker can induce the name server to cache fabricated data. In the most famous attack of this kind, Eugene Kashpureff poisoned the caches of hundreds of Internet name servers, leading them to direct users accessing to the IP address of a web server run by an organization called the AlterNIC.

It’s difficult to overstate the damage an attack like this could cause today: a hacker could redirect traffic intended for a bank’s web site to a web server with a replica of the site’s content, and steal account numbers and passwords; or siphon off traffic meant for a web-based merchant to an identical web site and capture credit card numbers.

 Difficult Upgrades

With BIND and Microsoft name servers, upgrading to a new version of the software
is non-trivial. Upgrading involves, at the very least, downloading new source code, compiling, testing, and installing it. In many cases, incompatibilities with previous versions force administrators to modify configurations or zone data or, worse, actually read the documentation. Consequently, many administrators put off the crucial task of upgrading their name servers when new versions are released.

 This can have disastrous effects. Months after a buffer overrun was discovered and patched in the code, the LiOn worm exploited the vulnerability to infect hundreds
of name servers around the Internet. The worm also installed a “rootkit,” which the worm’s author (or anyone else familiar with the worm’s operation) could use to gain root access to the infected host. The hacker could have modified or destroyed zone data, or in some circumstances could have used the name server as a stepping-stone into the unprepared company’s network. Even today, it is highly likely there are still name servers on the Internet that were compromised during LiOn’s spread, unknown to their administrators.

 Ever-Growing Attack Options

One of the biggest challenges for IT organizations is the varied and ever-changing options for DNS attacks. Common attacks include:


Attack TypeDescription
TCP SYN Flood AttacksA DDoS DNS attack, typically leaves “hanging” connections by flooding DNS server with new TCP connection requests until the target machine fails.
UDP Flood AttackA DDoS DNS attack, sends a large number of UDP packets to a random port on the targeted host to confuse or overwhelm the target machine until it fails.
Spoofed Source Address/ LAND AttacksA DDoS DNS attack, sends a spoofed TCP or UDP packet with the target host’s IP address to an open port as both source and destination. The reason this attack works is because it causes the machine to reply to itself continuously, therefore making it essentially unavailable to other applications.
Cache Poisoning AttacksA core DNS attack, poisons DNS cache typically in order to send legitimate requests to malicious websites.
Man in the Middle AttacksA core DNS attack, a compromised machine in the network can penetrate and take over the entire DNS structure and then route legitimate requests to malicious websites.

 There are many other ways a DNS server may be compromised, and newer, more complex methods are being devised all the time in the underworld of botnets, but these have happen with the most frequency and have characteristics common to many others.

 Aren’t General-Purpose Computers Good Enough for DNS?

 Most companies deploying external name servers have chosen computers running general-purpose operating systems as their platform. While this deployment may be inexpensive to deploy and may function, general-purpose servers have several major risks that actually increase the propagation of DNS attacks:

  • General-purpose operating systems require significant knowledge and effort
    to secure. Securing a UNIX OS requires understanding which network and system services should be disabled and how to disable them, which patches are necessary, which kernel modules and device drivers are needed and which are extraneous, how to configure UNIX packet filters, and much more.
  • In addition to patching the OS, the name server code itself frequently needs to be upgraded to address vulnerabilities or simply to add new features. This usually must be done separately from upgrading the operating system.
  • General-purpose OSs support user logins. Hackers can use these to gain administrator-level access to the operating system. Even in the best case, with secure logins and benign users, those users may inadvertently destabilize the operating system by installing software that consumes system resources, by filling disks, etc.
  • Most general-purpose operating systems offer all-or-nothing administration, empowering administrators to either change any aspect of the name server’s configuration and zone data, or nothing. Giving a junior administrator only limited access to the name server is nearly impossible.
  • Configuration of a name server’s internal security mechanisms is difficult, and consequently often ignored by even seasoned administrators.


Shortcomings of the conventional approach include:

  • Many open ports are subject to attack
  • Users have OS-level account privileges on server
  • Requires time-consuming manual updates
  • Requires multiple applications for device management
  • Inconsistent or outdated security procedures

 Securing Your DNS Infrastructure and Applications

Instead of relying on general-purpose servers and hoping your internal IT team will never leave a hole in the system, organizations can leverage purpose-built appliances with intuitive interfaces and embedded expertise to improve DNS availability and reduce the risk of DNS attacks.

Most IT executives understand the value of purpose-built solutions but implement general purpose servers because they think they are less expensive. However, the focused approach reduces the risk of configuration errors, supplies the expertise you need to have available, and reduces the cost of implementation and maintenance due to the risk reduction and staff empowerment.



Infoblox solutions

Infoblox helps organizations implement robust, secure, and manageable DNS infrastructure. By leveraging hardened appliances that run on patented GridTM technology, users eliminate the architectural challenges of general-purpose servers and reduce the risk of DNS attacks.

The Infoblox platform, Trinzic DDI, is an appliance-based network services software suite delivering state-of-the-art DNS, DHCP, and IP address management (DDI), with seamless and agentless integration to Microsoft servers. This Grid technology is an advanced, highly available, fault-tolerant, and massively scalable network solution that improves management and availability with centralized management and robust failover capabilities.


Secure DNS

More security, less risk

 It’s critical that the technology you deploy for network control provides maximum protection and offers minimum attack surface. Infoblox clearly differentiates from other vendors from a security perspective.

From our highly secure hardware form factor, to our hardened OS, to the variety of security features in our applications—no other network control vendor focuses more on security than Infoblox.

 The Infoblox Secure DNS Family of Products:


Internal DNS Security

Protect data and critical network infrastructure from targeted attacks

Today’s targeted attacks pose threats to both data and infrastructure inside your enterprise. Infoblox Internal DNS Security protects mission-critical DNS infrastructure from attacks, stops advanced persistent threats (APTs) and malware from using DNS, and prevents data exfiltration with an optional module, Infoblox DNS Threat Analytics.

Unlike alternate solutions, it combines Infoblox automated threat intelligence feed with enterprise-grade DNS to provide ongoing protection against new and evolving threats—leveraging the unique position of DNS in the network that makes it the optimal enforcement point for protection and response.

External DNS Security

Protect your external DNS from attacks

External DNS Security provides defense against the widest range of DNS-based cyber attacks such as DNS DDoS, NXDOMAIN, exploits, and DNS hijacking attacks.

Unlike approaches that rely on infrastructure over-provisioning or simple response-rate limiting, External DNS Security intelligently detects and mitigates DNS attacks while responding only to legitimate queries. Moreover, it uses Infoblox Threat Adapt™ technology to automatically update its defense against new and evolving threats as they emerge, without the need for patching

DNS Firewall

Protection from APTs and malware communicating with C&Cs and botnets

Infoblox leverages our market-leading DNS technologies into the industry’s first true DNS-based network security solution. Infoblox DNS Firewall prevents advanced persistent threats (APTs) and malware from exfiltrating data, by disrupting the ability of infected devices to communicate with command-and-control (C&C) sites and botnets.

DNS Firewall works by employing DNS response policy zones (RPZs), timely threat intelligence, and optional Infoblox DNS Threat Analytics to prevent data exfiltration—for effective protection. Furthermore, Infoblox is the industry’s first and only DDI vendor to seamlessly integrate DNS Firewall with leading security solutions such as FireEye and Bit9 + Carbon Black and exchange valuable security event information with NAC solutions such as Cisco ISE to automate security response and quarantine infected endpoints

DNS Firewall – FireEye Adapter

Proactive APT malware protection via early detection and rapid remediation

DNS Firewall integration with FireEye NX Series appliance using the FireEye Multi-Vector Virtual Execution (MVX) engine delivers a unique and powerful defense against Advanced Persistent Threats (APT) for business networks.

This solution combines the power of FireEye APT detection and Infoblox DNS level blocking and device fingerprinting — to detect and disrupt APT malware communication and help pinpoint infected devices attempting to access malicious domains. This is the first and only solution in the marketplace that invokes powerful DNS level control upon FireEye APT detection events.