To every CISO, security architect, and red team leader: If your attack surface management (ASM) platform isn’t mapping all 65,535 ports across IPv4 and IPv6, you’re defending an incomplete version of your organization. Adversaries on the other hand, attack everywhere.
This isn’t a technical nitpick, it’s a fundamental shortcoming in how most security tools operate. While many platforms scan only the most common ports (typically between 2,000 and 5,000), that leaves over 90% of the potential attack surface unchecked. Meanwhile, attackers scan the full space: all 65,535 defined ports in the 16-bit protocol range. This number isn’t an estimate or marketing flourish, it’s the technical boundary of the port space defined by IANA. It won’t change tomorrow.
If your visibility ends where their reconnaissance begins, you’re exposed in ways you may not realize until it’s too late.
The hidden 90% of the attack surface
Many organizations have implemented meaningful controls and risk mitigation strategies, but even the most well-managed environments are limited by the tools on which they depend. Most ASM solutions scan only default or “popular” ports, leaving the rest unmonitored. That creates blindspots not because defenders are careless, but because their tools don’t go far enough. According to the
World Economic Forum’s Global Cybersecurity Outlook, 91% of business and cybersecurity leaders believe a far-reaching and catastrophic cyber event is at least somewhat likely in the next two years, driven largely by geopolitical instability and an expanding digital footprint. Meanwhile, the vulnerability landscape continues to accelerate. Per
Qualys, by mid-2024, 22,254 CVEs were reported, marking a 30% increase over 2023 and a 56% jump from 2022.
The attack surface is growing. Exposure is accelerating. Tools that rely on assumptions instead of complete scans aren’t just outdated, they’re a liability.
Attackers exploit what you’re not looking at
Adversaries don’t skip ports because they’re uncommon. They don’t assume IPv6 is out of scope. They don’t operate with defaults or convenience, they scan everything. They don’t assume IPv6 is out of scope. If a service is reachable, whether it’s on port 443 or 52,432, they’ll find it and test it.
Security teams, meanwhile, are often constrained by tooling that narrows the scope of discovery by design. That hands a clear advantage to attackers who face no such limitations.
What comprehensive visibility requires
Truly effective ASM must go beyond fast scans and convenience-based defaults. It requires:
Discovery across both IPv4 and IPv6, which are increasingly used in parallel
Enumeration of all 65,535 TCP and UDP ports, not just the easy ones
Continuous visibility, not periodic snapshots
Contextual prioritization, informed by real-time threat intelligence on what adversaries are actively exploiting
If your tooling can’t do all of that, it’s not delivering the full picture, and it may be feeding your teams a false sense of confidence.
Proven at scale
The most security-conscious organizations such as governments, defense agencies, and critical infrastructure operators are moving toward solutions that offer full-port visibility and advanced computational mapping techniques. These approaches eliminate the need for manual input, reduce blind spots, and operate at the speed and scale required for modern hybrid environments.
In high-stakes sectors like finance and energy, defenders are embracing platforms that can scan up to 8x or 4x more ports, respectively, than traditional solutions, while consuming up to 90% less bandwidth than legacy approaches.
This isn’t theoretical. It’s operational and it’s already reshaping how leading organizations define and defend their external footprint.
Less dashboard, more truth
Security teams don’t need more dashboards. They need honest visibility: a complete contextual view of their external exposure and the threats actively targeting them.
Partial scans don’t reveal the whole picture. Fast isn’t enough. Today’s risks demand completeness.
A CISO’s call to action
Ask your team today: “How many ports are we actually scanning?”
If the answer isn’t all 65,535, the next question should be, “What are we not seeing?”
Visibility is the foundation of security. You can’t reduce a risk you don’t know exists. In a landscape where attackers are moving faster and targeting deeper than ever, partial views don’t protect, they mislead.
The future of defense starts with full visibility. And that begins with scanning everything.
