DNS security is concerned with implementing protection measures to prevent attacks on the Domain Name System (DNS). There are several aspects of DNS security that should be considered, with the best DNS security solutions plugging a gap in your security defenses to block common threats that are not fully addressed by other cybersecurity solutions.
Best DNS Security Measures
When the DNS was devised in 1983, cybersecurity was not a big concern. Security systems now need to be added to protect the DNS as it was never designed to be secure. DNS security is concerned with securing DNS infrastructure and blocking threats that leverage the DNS. Attacks on the DNS are common, yet it is an area of security that is often neglected.
When you make a request to access a web resource, that web resource must be located, which is what the DNS is used for. Requests are sent to a DNS server and an IP address for a resource is returned. DNS servers are often targeted to redirect users to malicious IP addresses, in denial-of-service attacks, man-in-the-middle attacks, and for communication and data exfiltration.
The Best DNS security measures to implement to block these attacks are DNS Security Extensions (DNSSEC), DNS over TLS, and DNS over HTTPS. DNSSEC addresses the vulnerability of DNS to man-in-the-middle attacks by using digital signature key pairs to verify that a DNS query comes from a proper source and validates each DNS server. DNS over TLS and DNS over HTTPS apply encryption to DNS plaintext queries, which also helps to prevent man-in-the-middle attacks and the interception of DNS queries. DNSSEC and one of the other two measures will improve your defenses against attacks on the DNS.
Since the DNS is a trusted protocol, it can be abused to hide communications. You should also be monitoring DNS queries to identify potentially malicious activity, such as communications between malware and their C2 server and use of DNS for data exfiltration. Intrusion detection systems (IDS), next-generation firewalls, and web filtering solutions often feature DNS inspection and can prevent the abuse of the DNS for C2 communications.
The Best DNS Security Products Block Web-based Cyberattacks
Businesses invest in cybersecurity solutions such as firewalls and spam filters to block cyberattacks, and while they are highly effective, they are not infallible. The key to mounting a formidable defense against cyberattacks is to adopt a defense in depth strategy, with multiple overlapping layers of protection. Should one security solution fail to block a threat, other protections will be in place to continue to provide protection. DNS-based security solutions should form part of your cybersecurity arsenal to block threats delivered via the Internet, one of the most important of which is DNS filtering.
With DNS filtering, a DNS query is made by an application or a browser to obtain the IP address to allow a particular resource to be accessed, but instead of the DNS server providing an IP address if that resource exists, the request is subject to filtering controls. Data packets will be inspected, unusual DNS activity will be detected, and if a prohibited or unusual request is received, that activity will be blocked.
Improve Phishing Protection
Spam filters are used to block phishing emails, but phishing emails can bypass email gateway defenses, especially those containing hyperlinks. If a user clicks a link in an email, they may be redirected multiple times before they arrive at the final destination. Anti-phishing solutions may not follow all of those redirects and may therefore not identify the link as malicious. It is also possible to send phishing emails with a benign hyperlink, then add malicious content after the email has been delivered. DNS filtering provides an additional layer of protection, delivering protection at the time the link is clicked.
Prevent Command and Control Server Communications
Malware often relies on the DNS for communication and to stage the infrastructure to support different stages of the attack, such as establishing a connection with a command-and-control server and for data exfiltration. DNS-based web filters can identify and block these C2 communications.
Prevent Malware Downloads
Malware is often downloaded via the Internet. A user could be directed to a malicious URL through a phishing email, general web browsing, or from clicking a link in a malicious advert – malvertising. Threat actors often sneak malicious adverts onto high-traffic sites through third-party ad networks. DNS-based web filters are fed threat intelligence from millions of users, which allow malicious websites to be rapidly identified and blocked. DNS-based web filters with machine-learning capabilities can also scan the content of websites in real-time and identify new threats.
Block Fake and Pirated Software Downloads
A common way for threat actors to trick individuals into downloading malware is to bundle malware with pirated software or add malicious code to fake apps. The sites offering the apps and software are promoted through search engine poisoning to appear high in the SERPs. Alternatively, pirated software available through peer-to-peer file-sharing networks can have malicious code added. When the software installers are executed, malware is delivered. Malware is also bundled into product activators and software cracks. DNS based web filters can be configured to block the downloading of these files, and block categories of websites – Warez and torrents sites for example – that are particularly risky.
Secure Web Browsing
Threat actors often purchase lookalike domains for hosting malicious content, which take advantage of typos when entering URLs in browsers – Often referred to as typosquatting or URL hijacking. These tactics take advantage of mistakes by users and can easily lead to a malware download. For instance, an individual typing gooogle.com of gogle.com could be directed to a malicious site where a drive-by download of a malicious file is triggered. The best DNS security solutions can block access to these malicious websites.
Content Control
Not all threats to the business are malicious. Other threats exist that can cause significant brand and reputation damage. If employees are given full access to the Internet, they could engage in activities that could damage a brand, contribute to the creation of a hostile working environment, or land a business in legal trouble. The best DNS security solutions protect against these issues by filtering the Internet and only allowing access to certain types of web content. They reduce legal risk by blocking illegal Internet activity, prevent access to undesirable content such as pornography, and can help to improve productivity by blocking access to gaming, dating, gambling, and social media sites.
Summary
You should take steps to protect against DNS attacks and ensure the best DNS security solutions are used. Measures to take include DNSSEC, encrypting DNS communications, and using a DNS-based web filtering solution to protect against cyberattacks via the web.
