The Domain Name System (DNS) contains records that provide information about any given domain name. These records include its corresponding Internet Protocol (IP) address, mail exchange (MX) server, and nameserver (NS), among other things.

All these details help locate a particular domain name when a user types it on a browser. The domain example[.]com, for instance, currently has the following details from its DNS records:

  • IP address: 93[.]184[.]216[.]34
  • Administrator: noc[.]dns[.]icann[.]org
  • NS: ns[.]icann[.]org

DNS records may change over time. For example, website administrators may need to point a domain to a different NS or IP address. So, what happens to the domain’s past DNS records? That is where DNS history comes in.

What Is DNS History?

Before 2005, the historical DNS records discussed above were lost forever after a certain amount of time. There was no way to store these records. However, Florian Weimer invented passive DNS (pDNS), a technology that logs all of a domain’s past DNS records.

There are several ways to look up DNS history records, such as using reverse DNS lookup tools or downloading pDNS databases.

3 Reasons Why Tracking DNS History Is Crucial

DNS history records have several uses, but their primary purpose is to fight off cyber attacks, particularly those that use malware. And these days, businesses have every reason to include cybercrime protection in their priorities since not doing so could be pretty expensive.

Therefore, monitoring DNS history is essential for companies, and below are three specific reasons why.

Detect Potentially Malicious Domains

One of the most critical insights that DNS history provides is a list of domain names that resolve to the same IP address. The malicious IP address 157[.]230[.]221[.]198, for instance, is connected to delta9k[.]com and five of its subdomains, including mumble[.]delta9k[.]com and registry[.]delta9k[.]com.

These domains and subdomains are not reported as malicious, so they may not be flagged by security systems that don’t implement IP-based blocking and monitoring. However, since they are the only ones resolving to the malicious IP address (at least at the time of writing), it could hint at involvement in suspicious activities. Networks are better protected if security teams inspect traffic to and from these domains and subdomains.

Several types of cyber attacks can be deterred by uncovering domains connected to malicious IP addresses. Phishing and malware campaigns are among these since they use domain names as weapons.

Help Prevent and Recover from DNS Hijacking

Regularly tracking your DNS history records helps you detect signs of DNS hijacking, a common type of DNS attack.

In DNS hijacking, threat actors modify your DNS configurations after gaining unauthorized access to your system. They can then change IP resolutions to redirect your website visitors to a site under their control. This website serves as a gateway for threat actors to steal sensitive user information from your network.

But if you immediately see a sudden change in IP resolution through DNS history monitoring, you can investigate and mitigate attacks before they can do more damage. Having access to your historical DNS records also helps recover them and correct modifications done by threat actors.

Protect Brand Reputation

Preventing and detecting any cyber attack early is a form of brand protection, as these processes help you avoid the reputational damage brought on by cybercrime. Aside from dubious IP addresses, DNS history allows you to stay away from suspicious cyber resources, such as NSs and mail servers that threat actors could use by detecting them before they are allowed access to your network.

DNS history also helps detect malware command-and-control (C&C) servers. This allows businesses to combat denial-of-service (DoS) attacks, which use a network of computers called a “botnet” to send false requests to a website until it is crippled and rendered unavailable to legitimate visitors. The botnets usually communicate with C&C servers, so taking down these servers would help stop the attack.

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Monitoring DNS records, both current and historical, is critical for businesses. Current DNS records help potential customers find your website, while DNS history records help retain and attract more customers by helping you avoid cyber attacks.