Cybersecurity Post-Incident Cleanup – What You’re Probably Not Doing

In the aftermath of a cyber incident, organizations often experience a sense of relief as they diligently implement remediation efforts. However, the deceptive nature of cyber threats can leave behind subtle traces that elude traditional post-incident tools, creating a potentially false sense of security. Cyber adversaries, skilled in deception, may strategically leave dormant elements or subtle backdoors that escape initial detection, necessitating a more nuanced and comprehensive approach.

Addressing the ongoing threat posed by cyber adversaries is crucial, considering that once infiltrated, they can remain undetected for an average of 99 days before discovery. This reality emphasizes the importance of adopting a holistic and proactive cybersecurity strategy that goes beyond the initial incident response activities.

The Role of DNS Traffic

A key aspect of fortifying cybersecurity post-incident involves understanding the role of DNS traffic. Nearly all cyber-attacks share a common thread – a DNS query. About 90% of attacks originate from phishing incidents involving compromised or malicious domains, and close to 80% involve DNS queries. Monitoring outbound DNS traffic becomes pivotal, as malware must communicate with Command & Control (C2) infrastructure through these queries to receive ongoing instructions.

Implementing continuous monitoring, particularly at the DNS layer, is crucial for early threat detection that may have been overlooked during initial remediation efforts. By keeping a vigilant eye on DNS traffic, organizations can identify and neutralize threats that may persist beyond the initial cleanup, fortifying their cybersecurity posture.

Digital Forensics and Incident Response (DFIR)

Seamless integration with existing security infrastructure is paramount for effective Digital Forensics and Incident Response (DFIR). The compatibility of monitoring solutions with various security tools enhances efficacy in ensuring a clean environment. This integration allows for a cohesive approach, preventing the oversight of potential threats that might go unnoticed when relying solely on individual security components.

Additionally, having a DNS solution that not only blocks communication with known bad domains but dynamically updates based on reputational and infrastructural analysis without the need for continual user interaction is crucial for saving time for both companies and analysts. This coupled with the ability to customize both block and allow policies gives security teams the control they need to shape traffic in a way that best fits their organization. Such tailored security measures align with specific needs and vulnerabilities, effectively preventing the persistence of threats post-incident.

HYAS Protect protective DNS is uniquely able to contribute to the digital forensics and incident response (DFIR) process. Download the solution brief.

Monitoring DNS Traffic

Delving deeper into the significance of DNS traffic monitoring reveals its dynamic nature and the unique insights it provides. Cybercriminals often leverage DNS queries as a means to initiate and sustain malicious activities. By scrutinizing outbound DNS traffic, organizations can uncover patterns indicative of malicious behavior, even when threat actors attempt to camouflage their activities.

DNS traffic monitoring provides a unique vantage point, offering insights into domain-based intelligence and attribution. This level of visibility allows security teams to proactively identify and neutralize threats before they can cause significant harm. Moreover, DNS traffic analysis aids in understanding the tactics employed by cyber adversaries, empowering organizations to fortify their defenses against evolving attack vectors.

To illustrate the real-world implications of comprehensive DNS traffic monitoring, consider a recent case of a very large telecommunications company. They suffered a breach and contacted all the right Incident Response (IR) companies to help them bounce back from the unfortunate discovery. Once the clean-up was completed, the telecom was given the, ”all clear” followed by a few hefty bills.

The telecom company was excited to get back to normal operations but wanted to do one last check before they considered the incident closed.

DNS Traffic Analysis

They chose to have a quick look at their outbound DNS traffic, something not considered by most teams, including the IR teams they hired for a comprehensive clean-up. This proved to be a game-changing decision. After some rapid analysis, multiple open and active communication pipelines to a prominent Asian country were found. Keep in mind, this was AFTER all the “clean-up” had been completed. Now, this is by no means a knock on the traditional DFIR techniques or the IR companies that perform them. Both are still VERY important and provide valuable information, tools, and services to help companies recover from a cyber-attack. However, this is a glaring example that we need to rethink what’s included in our DFIR plans.

Now, armed with actionable intelligence from DNS traffic analysis, the security team swiftly implemented measures to block IP addresses and domains associated with the attack, containing the threat within hours.

The immediate impact was the containment of the attack, significantly reducing additional damage. Moreover, the long-term benefits were equally noteworthy. The telecom firm, armed with insights from continuous DNS traffic monitoring, developed stronger security protocols. These insights were instrumental in adapting their cybersecurity posture to emerging threats, ensuring a more resilient and proactive defense strategy.

Best Practices for Post-Incident Response

This case study highlights several key lessons and best practices for organizations looking to enhance their cybersecurity posture post-incident:

1. Proactive Monitoring: Continuous monitoring, especially at the DNS layer, proved crucial for comprehensive threat detection and mitigation even when traditional methods fell short.

2. Integration with Existing Systems:Seamless integration with existing security infrastructure played a pivotal role in the effectiveness of Digital Forensics and Incident Response.

3. Customizable Threat Blocking:The ability to customize threat blocking based on risk tolerance provided the organization with the flexibility to adapt to evolving cyber threats.

In conclusion, the illusion of a completely clean environment post-incident is shattered by the reality of persistent cyber threats. Organizations must adopt a proactive, nuanced, and comprehensive approach to cybersecurity. Continuous DNS traffic monitoring emerges as a linchpin in this strategy, providing unparalleled visibility into malicious activities that may otherwise remain hidden.

By integrating suitable solutions, embracing continuous monitoring practices, and ensuring seamless integration with existing security infrastructure, organizations can fortify their cybersecurity posture. The case study underscores the practical implications of such an approach, demonstrating its effectiveness in both immediate incident response and long-term resilience against evolving cyber threats.

As the cybersecurity landscape evolves, staying one step ahead becomes not just a choice but a necessity for safeguarding digital assets and maintaining business continuity in the face of persistent and dynamic cyber threats.