Why Your Network is Your Best Defense: A Complete Guide to Threat Detection, Investigation, and Response

Your network sees everything. Every login. Every data transfer. Every suspicious packet trying to sneak past your defences.

In today's hyper-distributed IT environment, the role of the network in cybersecurity has never been more critical. With ever-expanding attack surfaces, increasingly sophisticated cyber threats, and the rise of AI-driven exploits, the network stands out as both a sensor and an enforcer in detecting and responding to these challenges.

In this technical deep dive, we'll unpack insights from Splunk and Cisco experts, explore real-world integrations, and showcase how modern SecOps can leverage the network to reduce risk and improve response times. Think of it as your network's origin story: from infrastructure to superhero.

A World of Complexity: Today’s Cybersecurity Landscape

Threat actors are evolving. And so are the environments they target.

As Craig Saunderson, Senior Strategic Adviser at Splunk, explains, organisations now operate in a complex, hyper-diverse IT landscape. With users spread across multiple locations and devices, coupled with hybrid IT infrastructures, maintaining digital resilience is anything but straightforward.

Cyber threats are prolific. And here's the thing: the attackers' entry points tend to be far less sophisticated than the damage they can inflict.

The Numbers Tell the Story

Consider this: the number of published vulnerabilities (CVEs) has skyrocketed from around 6,500 annually a decade ago to nearly 45,000 today.

That's a massive expansion of the attack surface. Bad actors now have a much broader landscape of weaknesses to exploit. Think of it as going from a modest buffet to an all-you-can-hack smorgasbord. At the same time, organisations striving to converge traditional IT and hybrid systems are challenged to stay adaptive, not just to reduce risk but to respond to ever-changing threats dynamically.

The Network as a Sensor: A Central Point of Truth

Here's what you need to understand: every cyberattack leaves its mark on the network.

Whether it's malware infections, data exfiltration, or lateral movement, attackers ultimately rely on the network for command and control (C2) traffic and data transfers. This makes the network a unique and indispensable vantage point for detecting threats.

Why the Network Tells the Full Story

Unlike endpoints, which might be powered off, tampered with, or wiped clean, network traffic tells the full story. It provides centralised, continuous visibility across devices, users, systems, and applications. NetFlow data, DNS requests, TLS handshakes, and packet captures can all reveal anomalous behaviour or malicious patterns.

As Aaron Osborne, Cisco SD-WAN expert, aptly puts it:

Not only does this "network-as-a-sensor" model enable earlier detection, but it also supports deeper investigations by correlating patterns across telemetry such as authentication logs, VPN activity, and system events.

The Network as an Enforcer: From Noise to Action

Detection without enforcement is just noise. That's where the "network-as-an-enforcer" concept comes in: the same network fabric that identifies malicious activity should also enforce policies and block threats in real-time.

How Splunk and Cisco Integration Empowers Your Network Splunk and Cisco's integrations empower the network to act as an enforcement layer, reducing mean time to detect (MTTD), mean time to respond (MTTR), and crucially, mean time to contain (MTTC). For instance, if an insider threat is identified during an investigation (say, a bad actor leveraging legitimate credentials), network policies can isolate compromised devices and block further lateral movement instantly. The power of this combination lies in unifying telemetry data for richer visibility and smarter automated responses. With Splunk's robust analytics and Cisco's integrations, the network becomes a hub for both proactive detection and swift remediation. Your network goes from passive observer to active defender.

Real-World Use Case: The Enterprise Networking App for Splunk

To truly harness the power of network data, organisations need a way to consolidate and act on it effectively. Enter the Cisco Enterprise Networking App for Splunk. This solution simplifies complex data ingestion, correlation, and analysis workflows by bringing together telemetry from across Cisco products within a single Splunk interface.

For example, imagine a scenario where a user, Alfred, reports an issue with application access. By checking the Splunk dashboards powered by the Enterprise Networking App, SecOps teams can:

• Gain visibility into network health metrics (e.g., uptime, host health scores).
• Investigate dropped firewall logs to identify hits on restrictive access policies.- Correlate endpoints, user activity, and device connections via ICE (Identity Services Engine) telemetry.

During the investigation, the team discovers that Alfred’s device hit a quarantine policy due to poor posture. By isolating his device and providing remediation steps, they restore business continuity while minimising risk to the broader network.

Delivering TDIR: Threat Detection, Investigation, and Response

At the heart of modern SecOps is TDIR—Threat Detection, Investigation, and Response. To support this capability, Splunk and Cisco focus on four key pillars:

1. Data

It’s not about having all the data in Splunk; it’s about having the right data available in the right place. For example:

• Real-time detections use telemetry like successful east-west firewall traffic.
• Deeper investigations require federated searches across data lakes like Amazon S3.

2. Analytics

Analytics should model threats based on industry-specific risks and threat actor behaviour.

For instance, retail organizations may prioritize detecting insider IP theft, while manufacturing companies focus on preventing ransomware.

3. Automation

No SOC can keep up with the scale of today’s threats without automating repetitive tasks. For example, phishing response workflows in Splunk SOAR can auto-remediate up to 60% of incidents, freeing analysts to focus on higher-priority threats.

4. AI and Machine Learning

Splunk employs AI-powered capabilities like risk-based alerting and anomaly detection to enhance visibility and predictions. With prebuilt machine learning models, organisations can detect patterns associated with DNS tunneling, C2 traffic, and malware behaviour more effectively.

Case Example: Automating Threat Analysis with Splunk Attack Analyzer

As demonstrated in the webinar, integrating Splunk ES, SOAR, and Threat Analyzer automates time-consuming tasks like malware analysis. Here’s how it works:

1. Detection: A suspicious URL is flagged in Splunk ES.
2. Automation: With a click, the URL is submitted to Threat Analyzer, which detonates payloads, extracts hidden IOCs, and uncovers malware behaviour in seconds.
3. Insights: Threat Analyzer outputs a detailed report with verdicts and MITRE ATT&CK; mappings, reducing manual workload for analysts.

In one scenario, a phishing attempt included malicious SVG files (a growing attack vector). Threat Analyzer detected embedded JavaScript and flagged C2 traffic, allowing the SOC to respond proactively before damage occurred.

Actionable Takeaways

To elevate your TDIR capabilities with Splunk and Cisco:

• Enhance Visibility: Treat the network as both a sensor (for detecting anomalies) and an enforcer (to isolate threats).
• Leverage Integrations: Use tools like the Cisco Enterprise Networking App for Splunk to unify and simplify telemetry analysis across your environments.
• Automate Smartly: Deploy Splunk SOAR to offload repetitive processes, such as phishing response, while integrating Threat Analyzer for automated payload investigations.
• Adopt Risk-Based Alerting: Focus your team’s time on high-fidelity alerts and potential attack chains rather than sifting through siloed data.
• Invest in AI & ML: Use prebuilt models in Splunk to proactively detect patterns of malicious behaviour, enabling earlier and deeper investigations.With the right tools and approach, the network can become your strongest ally in safeguarding your organisation against modern threats. Ready to get started?

Explore Splunk Integrations with Cisco to Unify Security and Networking

By leveraging the complementary strengths of Splunk and Cisco, your SOC can achieve faster detection, smarter investigation, and automated responses that keep your organisation secure.