Why Network Visibility Matters

Many security teams rely on Proxy and Web Application Firewall (WAF) logs for visibility, but that’s only part of the picture.

🛡️ Firewalls, especially their allowed traffic logs, reveal critical activity that other tools can’t see.

🔍 They’re essential for detecting, investigating, and preventing threats across the entire attack lifecycle, from the first probe to the final exfiltration attempt.

✨ Where to Start

To unlock this visibility and close detection gaps, focus on the following six best practices.

We’ll begin with the foundation: capturing Layer 3/4 network visibility.

🌐 1. Capture Layer 3/4 Network Visibility

What to do

• Ingest allowed firewall traffic (not just HTTP/S) across all protocols and east-west flows.

• Keep this data in your SIEM so analysts can query across users, hosts, apps, and segments.

Why it matters

• Provides foundational L3/L4 visibility and fills gaps left by Proxy/WAF.

• Eliminates blind spots in non-web communications and unmanaged assets.

Outcomes you unlock (examples)

• Detection across Initial Access, Lateral Movement, C2, Exfiltration stages.

• Discovery coverage, e.g., Network Service Scanning and Remote System Discovery.

🔍 2. Support Threat Hunting & Retrospective Analysis

What to do

• Retain allowed firewall logs for at least several months (align with compliance requirements).

• Store in a SIEM or long-term archive that allows fast retrieval and searching.

• Use the data for both scheduled hunts and ad-hoc investigations.

Why it matters

• Threat intelligence often arrives after an incident — without historical logs, you can’t verify exposure.

• Supports root cause analysis by enabling analysts to reconstruct attacker movement and tactics.

• Fills visibility gaps left by tools focused only on blocked or web traffic.

Outcomes you unlock (examples)

• Proactive detection of previously undetected threats.

• Ability to pivot on new IOCs, TTPs, or suspicious patterns over weeks or months.

• Evidence preservation for compliance or legal review.

📊 3. Enhance SIEM Correlation & Alert Accuracy

What to do

• Forward allowed firewall logs into your SIEM alongside proxy, WAF, endpoint, and identity data.

• Build correlation rules that link network, user, and application events across multiple data sources.

• Use context from multiple layers to refine alert logic and reduce false positives.

Why it matters

• Single-source detections can miss multi-stage or blended attacks.

• Cross-layer correlation uncovers attack paths that wouldn’t be obvious from one log type alone.

• Improves SOC efficiency by prioritizing true positives with rich context.

Outcomes you unlock (examples)

• Early detection of coordinated or chained attack activities.

• Higher-fidelity alerts that require less analyst triage.

• Better situational awareness during incident response.

🕵️‍♂️ 4. Strengthen Forensic Investigations

What to do

• Retain and index allowed firewall logs so they can be searched quickly during incident response.

• Use them to map out full attacker timelines, from entry point to data exfiltration.

• Combine with other security logs to get a complete view of attacker actions.

Why it matters

• Without network-layer data, incident timelines are incomplete and may miss key attacker steps.

• Identifies lateral movement, data staging, and exfiltration channels that other tools may overlook.

• Provides concrete evidence for post-incident reporting and root cause analysis.

Outcomes you unlock (examples)

• Faster containment by understanding exactly where attackers have been.

• Stronger incident reports backed by verifiable network data.

• Clearer insight into attack scope for executives, regulators, and legal teams.

🧑‍💻 5. Monitor for Insider Threats & Behavioral Deviations

What to do

• Feed allowed firewall logs into User and Entity Behavior Analytics (UEBA) tools.

• Establish baselines for normal user, host, and service activity.

• Create alerts for deviations such as unusual data transfers, rare protocol usage, or unexpected access patterns.

Why it matters

• Some of the most damaging breaches come from insiders or compromised internal accounts.

• Legitimate but suspicious actions (e.g., excessive file downloads) may bypass traditional security controls.

• Early detection of subtle changes in behavior can prevent data loss or abuse.

Outcomes you unlock (examples)

• Identification of slow, stealthy data exfiltration attempts.

• Detection of account misuse or credential compromise.

• Increased confidence in security posture against internal risks.

📜 6. Meet Compliance & Audit Requirements

What to do

• Enable logging of all allowed firewall traffic and retain it per your industry’s compliance standards.

• Store logs in a way that supports auditor access and legal evidence preservation.

• Regularly verify retention periods and storage integrity.

Why it matters

• Many regulations (PCI-DSS, NIST, ISO 27001, etc.) require comprehensive network activity logging, not just blocked events.

• Proper log retention supports investigations, regulatory reporting, and legal proceedings.

• Gaps in logging or retention can lead to compliance failures, fines, and reputational damage.

Outcomes you unlock (examples)

• Faster and smoother compliance audits with complete network activity records.

• Stronger legal position through preserved forensic evidence.

• Demonstrable adherence to security and privacy regulations.

Appendix – Technical Reference for Securonix Policies

This appendix provides the technical depth behind the best practices outlined above.

It is designed for security engineers, SOC analysts, and compliance teams who want to see:

• The specific MITRE ATT&CK coverage enabled by allowed firewall logging

• High-value detection categories and how they map to Securonix out-of-the-box (OOTB) content

• Retention guidance to support both compliance and security goals

• Implementation steps to ensure full visibility

📌 Summary of Recommendations

Before diving into the detailed tables, here’s a quick recap of what to implement:

1. Enable logging for all allowed firewall traffic — including internal (east-west) and external flows.

2. Forward logs to your SIEM in near real-time for correlation and detection.

3. Use historical logs for both proactive threat hunting and retrospective investigations.

4. Integrate with UEBA to detect insider threats and anomalies.

5. Correlate with proxy, WAF, and endpoint data to improve detection accuracy.

6. Retain logs per compliance and operational needs — generally 6–12 months is ideal.

7. Baseline normal behavior to strengthen anomaly-based detection.

8. Review and tune detection rules monthly using historical data.

📊 How to Use the Tables

The tables in this appendix are organized into:

• A. MITRE ATT&CK Coverage Map — which tactics and techniques are addressed.

• B. High-Value Detections & Securonix Policies — grouped by threat category (Data Exfiltration, External Threats, Reconnaissance & Exploitation, Insider Threat & Misuse).

• C. Retention & Storage Recommendations — how long to keep logs and where.

• D. Quick Implementation Checklist — to ensure complete coverage.

Color Key: 🟥 High | 🟨 Medium | 🟩 Low

📦 A. MITRE ATT&CK Coverage Map

This table shows the primary MITRE ATT&CK tactics and techniques enabled by forwarding allowed firewall logs into your SIEM.

It’s organized by tactic so security teams can map detections to known adversary behaviors.

📤 B.1 Data Exfiltration

Allowed firewall logs enable detection of malicious or unauthorized data movement, including covert or non-web channels.

These detections help identify both external exfiltration attempts and internal misuse of data transfer services.

🌍 B.2 External Threats

🛠️ B.3 Reconnaissance & Exploitation

Allowed firewall logs detect scanning, enumeration, and exploitation attempts that may not be caught by web-focused security tools.

These detections help identify both external probing and internal misuse aimed at discovering systems or exploiting vulnerabilities.

🕵️ B.4 Insider Threat & Misuse

Allowed firewall logs can reveal suspicious but authorized actions by legitimate users or compromised accounts.

This includes credential misuse, account sharing, and unauthorized access to internal systems.

🗄️ C. Retention & Storage Recommendations

Proper log retention ensures you can support incident response, threat hunting, compliance, and legal requirements.

Retention periods should be based on regulatory mandates and security operations needs.

✅ D. Quick Implementation Checklist

Follow these steps to ensure full visibility and effective use of allowed firewall logs:

1. Enable logging for all allowed firewall traffic — including internal, external, and east–west flows.

2. Forward logs to your SIEM in near real-time.

3. Tag and classify traffic as internal, external, or east–west for better correlation.

4. Retain logs based on compliance and operational requirements.

5. Baseline normal behavior for users, hosts, and services.

6. Integrate with UEBA for anomaly and insider threat detection.

7. Correlate with proxy, WAF, and endpoint data for improved detection accuracy.

8. Review and tune detection rules monthly using historical data.