DNS Security Best Practices
DNS security best practices are essential for every organization since they are critical to nearly all operations that involve networked applications. It allows communication between networked applications. DNS is also extremely complex in theory and implementation.
Cyber adversaries are increasingly focusing on the attack of DNS infrastructure. Applications cannot communicate with the DNS service if it is unavailable. This could cause essential operations to be halted. DNS security best practices are important to ensure the availability and health of DNS infrastructure.
These DNS Security Best Practices will ensure DNS’s reliability and security.
1. Ensure DNS logs all activity – This is one of the most important DNS Security Best Practise
Security professionals recommend DNS logging as a good strategy to monitor DNS activity and events. DNS logs can provide valuable insight into malicious attempts to interfere with DNS servers. DNS debug logs are used to identify issues in DNS queries or updates.
DNS also reveals any traces of cache poisoning. A cyber attacker can alter the DNS cache data to target clients by using malicious inputs. The DNS server may redirect clients to malware infested sites by changing an IP address from a legitimate website. These actions could compromise security for an entire company. While DNS debug log logging is essential for strengthening DNS security, system administrators may choose to disable it in order to increase performance. Monitoring network activity allows for timely detection of attacks such as Distributed DDoS (DDoS).
2. Secure the DNS cache
DNS stores query information from clients and places it in a cache for future reference. This improves the speed of DNS servers responding to clients who make the same query again.
However, cybercriminals could exploit this feature to modify the information. To complement the DNS debugging log feature, it is essential to lock the DNS cache. This is a good practice that allows system administrators to decide when to modify cached data. The DNS server stores only the lookup information that is relevant to the time specified in the time-to-live (TTL) setting.
The cache lock can be disabled so that store information can easily be altered or overwritten prior to the expiry of TTL. This opens the door for cache poisoning attacks. Companies can enable default cache locking depending on their operating system. To prevent any alteration of cache information beyond the expiry of the TTL, the scale of the locking cache can reach 100%.
3. Allow DNS filtering
DNS filtering is a way to prevent users from accessing malicious websites. It allows administrators to block the name resolution of sites or domains that contain malicious content. The DNS server immediately stops all communication if a client continues to send a query asking for access to a blocked site. DNS filtering reduces the risk of malware and viruses getting into the organization’s network. Security control prevents potential security threats to IT infrastructure from reaching clients by blocking malicious websites. IT security professionals do not need to keep up with dangerous malware.
A company might also seek to block certain domains according to its IT policies. Many organizations block certain websites to protect their employees’ productivity. These domains include video streaming, illicit material and social media sites, as well as gambling sites. Administrators can filter DNS requests based on groups or individuals or block all users from accessing certain websites.
Modern firewall software security solutions often include standardized DNS filtering. Companies can use such appliances to keep a list of malicious domains. This information is updated frequently. Automated DNS filtering can be used by organizations to avoid manual entries that are inefficient and inefficient.
4. DNSSEC is used to verify the integrity of DNS data.
Domain Name System Security Extensions allows clients to only receive valid answers to their queries. DNSSEC digitally signs DNS data that is sent to name servers. This ensures security and integrity. The DNS server verifies that a client has submitted a query and that it has received a valid digital signature. This allows clients to trust the information. DNSSEC adds an extra layer of security to protect against DNS protocol attacks.
DNSSEC also provides data integrity and origin authority, so attacks like DNS spoofing and cache poisoning can be avoided. Therefore, clients can be confident that they will visit the correct pages.
5. Assure that access control lists are correctly configured
To protect DNS servers against spoofing attacks or unauthorized access attempts, access control lists are essential. Only the system administrator and IT administrators have access to the primary DNS in order for the DNS servers’ security. Only legitimate clients will be able to communicate with DNS servers if they are configured correctly in the access control list.
Access control lists should also be used to define servers that are allowed to perform zone transfers. Cyber enemies may use secondary DNS servers in order to send zone transfer requests and determine the organization network zone setup. Cybercriminals can’t obtain zone information by blocking zone transfer requests through secondary DNS servers. These configurations are essential because they prevent malicious or unauthorized third parties from understanding the organization and structure of the internal network.
6. Separate authoritative and recursive name server
To identify a name and its IP address, the authoritative name servers scans the local database. The recursive names servers, on the other hand search a hierarchy if additional name servers to identify a name as well as the associated IP addresses.
To isolate and seperate roles according to network logical views, companies should use authoritative and recursive name server machines. System administrators should configure authoritative name server machines so that only authoritative name servers can send DNS update notifications. Corrupted or fraudulent database entries can have devastating consequences since authoritative name servers do not have the ability to cache.
7. Anycast can be used to enable forwarding routers that redirect DNS queries.
Anycast is used by routers to allow multiple servers to use the same IP addresses, and to send network communication and messages instead to a specific server. Anycast is used by name servers to show resilience, reduce the impact of DDoS attacks to mitigate them, and share a load.
Anycast improves the resilience of a network because routers can be dynamically configured to redirect traffic to the nearest server. Anycast can redirect traffic to the nearest server if a company disengages a server from its network. The strategy increases the system’s surface area. This exposes the network to security threats and attacks. It helps reduce DDoS attacks by spreading traffic among various servers.
8. Install dedicated DNS appliances
DNS applications, like most network appliances are built to serve a particular purpose. Both software and hardware are designed with security, performance, ease-of-management, and safety in mind. Operating system servers are not equipped with the same capabilities or levels of tuning as dedicated DNS appliances. The benefits of using dedicated DNS applications are similar in nature to other network appliances. They maximize the Random Access Memory (RAM) availability, limit driver requirements, reduce chatter between different networks over interfaces, and limit unnecessary ports.
By leveraging purpose-driven appliances within DNS architecture, it is possible to remove all unnecessary drivers and protocols. This greatly reduces the attack surface. These targeted functionalities allow security features like monitoring and logging to be focused on certain protocols and services. Activities like audit logging and change tracking can be greatly enhanced to target relevant security functions.
9. Regularly update the DNS server
Cyber adversaries will continue to seek out security holes in DNS server software. DNS is a prime target for attacks because it allows adversaries to use the DNS servers for data exfiltration as well as command and control attacks. These risks highlight the importance of making sure that the DNS server software is up-to-date to protect against attacks. The independent server design can make it difficult to install security updates and updates on time. This is because the process is per-server. A centrally managed solution is the best way to install architecture-wide updates. Organizations must also be proactive when deploying security patches, as DNS servers are resilient, and they do not give warnings if they become outdated.
10. Recursive DNS queries should have a time limit for response
Respondent rate limiting is a technique that allows authoritative name servers to respond quickly to queries from specific IP addresses. Name server programs such as NSD and Knot support a response rate limiting. The response rate limiting is used by a name server to keep track of the number of times it has answered the same question. The response time of the name server increases if the rate is higher than the threshold. The configured threshold will prevent the name server from responding to queries faster than the specified threshold. DDoS attacks are not possible on a name server that is compliant with the response rate limiting.
11. Hide the primary DNS Server
System administrators must hide their primary DNS server from public view. They should make the DNS servers visible to all users as slaves and designate the primary DNS server as a master server. Hidden or stealth master names servers do not store the NS records in a DNS server accessible to the public. Public access is restricted to the slave name servers. Public interrogation of name servers via query transfer or zone is prevented by the master and slave architectures. The architecture protects the integrity and confidentiality of DNS databases for slave name servers, since only the master server can push the operation to upgrade slave servers.
12. Configure the DNS socket pool
DNS socket pool allows the DNS server to use random source ports in DNS lookups. The DNS server can randomly select a source port from an idle socket pool by using the random ports. Instead of using the same port for multiple operations the DNS server chooses a random port out of the pool. This increases the difficulty in guessing the source port that is used to answer source port DNS queries. This configuration is supported by some operating systems.
13. Reset the name servers
Name server computers must only run the installed operating system and name server software. Name server computers should play a role in supporting network activities. Hacktivists will not install any other software products on the name server computer. Additional software can slow down the performance of the nameserver computer and cause it to crash if there are bugs. A name server must have a network connection to acquire updates and respond to DNS queries. The attack surface can be expanded by adding network cables or opening ports.
14. Redundancy and high availability of DNS
DNS is the communication foundation of network applications. It must be available 24 hours a day. A minimum of two DNS servers should be deployed within an organization to ensure redundancy. Two servers are sufficient to ensure that business-critical services run smoothly. Good DNS operations are essential for vital services such as email, file share, and active directory. To ensure that internal devices and applications communicate constantly, it is important to have redundant and high-availability functional and healthy DNS servers.
DNS Security Best Practices – Summary
These DNS security best practices will help ensure your organization is protected against hackers who may target DNS. Do you have any suggestions, comments, or a DNS Security Best Practice that we should add to this list. Leave a comment to let me know.