Securing Your External Attack Surface

Service Overview

Your external perimeter is often the first point of contact for adversaries seeking to infiltrate your organisation. Misconfigured systems, forgotten development environments, and exposed services can provide attackers with direct paths to internal networks.

SilentGrid’s Perimeter Assessment identifies and maps Internet-facing assets across your organisation, uncovering weaknesses that could be exploited. This service goes beyond simple asset discovery – we evaluate misconfigurations, outdated systems, and vulnerable services that could leave your organisation exposed to compromise.

Our proactive approach ensures that all external assets are accounted for and secured, minimising the risk of unintended exposure.

Why Perimeter Assessments Are Critical

The Growing External Attack Surface

As organisations expand their digital presence across cloud platforms, third-party services, and global infrastructure, managing external assets becomes increasingly more complex.

Perimeter Assessments provide visibility into the following risks, ensuring your organisation maintains control over what is exposed to the Internet:

• Unknown Systems – Development or test environments left online.
• Shadow IT – Unmonitored systems spun up outside official processes.
• Legacy Exposure – Forgotten or unpatched systems presenting vulnerabilities.

SilentGrid’s Approach to Perimeter Assessment

SilentGrid combines advanced reconnaissance techniques, threat intelligence, and active testing to provide a comprehensive view of your external attack surface. Our assessments identify not only the obvious points of exposure but also the hidden vulnerabilities adversaries actively seek.

Our Methodology

1. Passive Reconnaissance

   • Leveraging OSINT, DNS enumeration, and internet-wide scans to identify exposed assets without direct interaction.
   • Mapping subdomains, third-party integrations, and cloud environments.

2. Active Enumeration

   • Actively probing for misconfigurations in public-facing services, web applications, and network devices.
   • Testing for open ports, insecure protocols, and service misalignment.

3. Vulnerability Identification

   • Detecting known vulnerabilities in exposed services.
   • Assessing patch levels, outdated software, and misconfigured service implementations.

4. Targeted Exploitation (Time-Boxed)

   • Simulating real-world adversary attempts to validate exploitability of identified systems.
   • Testing for credential stuffing, default passwords, and weak configurations.

Deliverables and Reporting

SilentGrid’s perimeter assessment provides detailed, actionable intelligence to reduce external risk.

You will receive:

• Comprehensive Asset Inventory – A full list of identified Internet-facing assets, subdomains, and third-party systems.
• Risk Prioritisation – Highlighted vulnerabilities ranked by severity, exploitability, and potential business impact.
• Attack Surface Analysis – Visual mapping of external entry points, including open ports, misconfigurations, and exposed APIs.
• Remediation Guidance – Clear, practical steps to harden exposed services and mitigate risk.
• Executive Summary – High-level reporting for stakeholders, outlining key exposure points and strategic recommendations.

Beyond the Assessment – Strengthening Defences

A perimeter assessment is often the first step in developing a resilient external security posture. While valuable on its own, the findings serve as the foundation for more targeted security efforts.

Next Steps:

• Web Application Penetration Testing – Focus on critical web applications exposed to the Internet to uncover application-level vulnerabilities.
• Infrastructure Penetration Testing – Test your external infrastructure for unpatched systems, network misconfigurations, and lateral movement paths.
• Assumed Breach Exercises – Simulate the post-compromise phase, testing internal defences and incident response capabilities once an external foothold is established.
• Continuous Perimeter Monitoring – Regularly reassess your external perimeter to ensure new assets are accounted for and secured.

SilentGrid partners with organisations to provide long-term visibility into evolving attack surfaces, ensuring that as your environment grows, your security keeps pace.

Why SilentGrid?

SilentGrid’s Perimeter Assessment is conducted by security researchers, penetration testers, and adversary simulation experts who understand the nuances of external attack surfaces.

Our Expertise:

• Custom Tooling and Reconnaissance – We employ proprietary tools and methodologies to uncover assets that automated scanners miss.
• Real-World Adversary Techniques – Our approach reflects how real attackers operate, ensuring comprehensive coverage.
• Continuous Innovation – We stay ahead of new reconnaissance tools, shadow IT risks, and emerging external attack paths.

Is Perimeter Assessment Right for You?

Perimeter assessments are ideal for organisations that:

• Operate large, distributed, or cloud-integrated infrastructures.
• Require visibility into forgotten, misconfigured, or unmonitored Internet-facing assets.
• Are preparing for regulatory audits or compliance reviews that demand complete asset inventories.
• Need to reduce external attack surfaces as part of broader security initiatives.

Get Started with Perimeter Assessment

SilentGrid’s perimeter assessment service provides the foundation for securing your external assets and minimising attack surfaces.
Contact Us to schedule an engagement and take the first step toward reducing your external exposure.