How Malware Evades Detection with DNS Tunneling & How to Stop It

These terms sound a bit technical, but they are very significant in protecting your business against cyberattacks — DNS Tunneling, Malware Prevention, SOC Monitoring. Cyber criminals employ complex approaches to bypass security frameworks, one of those sneakiest approaches is DNS tunneling.

But let’s simplify it, break it down. What is DNS tunneling? How does malware exploit it? And perhaps most crucially, how do we end it? Let’s dive in.

What is DNS Tunneling?

You can imagine DNS (Domain Name System) is like a phonebook of the internet. When you type in a website URL, DNS converts it into an IP address to allow your browser to open the site. It is constantly changing (and infrequently checked for anomalous behavior) rendering it a prime target for attackers.

DNS tunneling is a method for hackers to sneak malicious traffic into DNS queries. Instead of normal web browsing, attackers hide malware traffic within benign-looking DNS requests and responses.

What Makes DNS Tunneling an Attractive Option for Hackers?

• No Direct Traffic – Most security tools monitor HTTP/HTTPS without checking the DNS.
• Bypasses Firewalls – With traditional firewalls, DNS traffic is typically allowed, so bad traffic can slip right under the radar.
• Stealthy & Persistent – Attackers can lurk for years inside a system without triggering alarms.

Now that we know what DNS tunneling is, let’s see how malware uses it to communicate.

How Malware Uses It

The malware uses DNS tunneling for trick communication between the infected devices and the hacker-controlled server. Here’s what that process looks like, step by step:

1. Infection

Phishing emails, malicious downloads or other attack vectors are used to install malicious software on a victim’s machine.

2. DNS Requests as a Cover

Rather than directly linking to a hacker’s server, the malware encodes and sends small pieces of stolen data or receives instructions from the attacker using DNS queries.

3. Remote Control & Data Theft

• Hackers embed stolen data into data encodes in subdomains they request in DNS.
• That infected system makes these requests to a bad DNS server.
• The hacker interprets the queries and retrieves sensitive information or runs commands on the victim network.

4. Constant & Secret Communication

Even with monitoring, malware can misuse DNS for months without setting off alarms. Security teams surveilling network traffic might not be alerted because DNS queries seem normal.

Scary, right? But don’t fret — there are simple ways to spot and prevent DNS tunneling before any damage is done.

Proven Tactics for Detection & Prevention

Preventing DNS tunneling is a matter of anomaly detection, limiting unnecessary access, and continuous monitoring. Here’s what we can do:

1. Monitor DNS Activities & Behavior

• Keep an eye on for large numbers of DNS queries to unknown domains.
• Look out for queries with weird unicode strings – this can be a form of embedded data.
• Build SOC monitoring to alert on real-time suspicious patterns.

2. Threat Intelligence & Blacklists

• Maintain a real-time threat intelligence feed to prevent access to known malicious domains.
• Block requests to malicious or recently registered domains.

3. Setup DNS Filtering & Logging

• Implement DNS filtering for blocking access to both allowed and disallowed domains.
• Maintain detailed logs of DNS queries to aid forensic investigation should an attack occur.

4. Segment Your Network

• We should lock down with firewall rules to ensure that our internal devices are unable to make external DNS requests.
• Tunnel all DNS traffic through only the sanctioned servers.

5. Machine Learning & AI Based Detection

• Detect anomalous DNS activity with AI-based security solutions.
• Automatically block unusual query patterns.

Such approaches prevent malware from exploiting DNS tunneling for attack operations. But security is a never-ending exercise. Enter PJ Networks’ DNS Security Solutions.

PJ Networks’ DNS Security Solutions

Solution for DNS tunneling detection and prevention at PJ Networks. Here’s how:

1. SOC Capabilities & Advanced DNS Monitoring

• 24/7 SOC monitoring for detection and resolution of DNS-based threats.
• Anomaly detection powered by AI for prevention.

2. Real-time Domain Blacklisting

• Real-time domain blacklisting to protect against known-bad hosts.
• Business customized DNS security policies.

3. Custom Security Strategies

• Network segmentation & firewall rules to prevent abuse of DNS.
• Deploy zero trust security model to minimize attack surfaces.

4. Incident Response & Forensics

• Review of DNS logs to identify malicious access.
• Triage your malware and data breach response.

You don’t have to figure this out alone. While DNS tunneling is a real threat, organizations can mitigate these types of attacks if they have the right security tools and expertise on their side.

Conclusion

As a secretive technique for exfiltrating data and bypassing security, DNS tunneling is a favorite among hackers. But just because it’s sneaky doesn’t mean it can’t be stopped. Data is used to measure risks in order to monitor and filter DNS along with applying machine learning analytics and rigid security policies to detect and prevent any form of DNS abuse by malware.

How PJ Networks Can Help

What We Do:

• DNS Security
• Malware Prevention
• SOC Monitoring

Ready to secure your network and start hunting down those hidden threats?