Remote and hybrid working stretched the attack surface of every business that adopted them, and the new shape stuck. The corporate perimeter that once mapped neatly to a building now sprawls across home offices, coffee shops, co-working spaces, and the occasional holiday rental. External testing matters more in this environment, not less, because the attacker no longer needs to find their way into the office. They simply need to find one weakness on any of your public-facing services.
The Perimeter Got Larger Without Anyone Noticing
When the workforce dispersed, the things they needed access to multiplied. VPN concentrators, remote desktop gateways, identity providers, virtual desktop infrastructure, conferencing platforms, and cloud applications all became visible to the internet because they had to be. Each new public service expands the attack surface. Without a corresponding expansion in testing scope, the gaps add up faster than anyone can patch them.
VPNs and Gateways Top the Target List
Major incidents involving Pulse Secure, Fortinet, Citrix NetScaler, Ivanti, and others have shown that perimeter access products attract sustained attention from sophisticated attackers. Patches arrive, but exploitation often happens within days of disclosure, sometimes hours. external network penetration testing performed regularly catches these systems before someone else exploits them. It also flags configuration issues such as outdated cipher suites, exposed admin interfaces, and default credentials that scanners can miss in their default modes.
Expert Commentary
Name: William Fieldhouse
Title: Director of Aardwolf Security Ltd
Comments: The remote access devices I find on first scans rarely match what the IT team thinks is exposed. Old test gateways spun up during the pandemic, forgotten Citrix instances from a decommissioned division, second-hand SSL certificates pointing to retired infrastructure, all sitting on the public internet, all available to the next opportunistic scanner.
Authentication Surfaces Demand Special Attention
Public-facing login pages handle a constant flow of traffic, much of it hostile. Credential stuffing attacks, password spraying, and account takeover attempts run continuously. Multi-factor authentication helps, but only when implemented properly across every authentication surface. A single unprotected legacy endpoint can become the entry point for a much wider compromise. Testing should specifically probe the consistency and effectiveness of authentication controls across all exposed services, not just the marquee login pages.
Cloud-Hosted Services Need the Same Scrutiny
External network testing is no longer just about your IP ranges. Your SaaS deployments, developer environments hosted in cloud accounts, and third-party integrations also count. Tenant misconfigurations in services such as Microsoft 365, Salesforce, or AWS often expose more than the network layer reveals. Comprehensive external testing reaches into these surfaces too, looking at the things an opportunistic attacker would notice during basic reconnaissance.
Establishing a Sensible Cadence
Quarterly external testing fits most mid-sized businesses with a remote workforce, particularly those handling regulated data. Combine it with continuous discovery so that new assets feed into the next assessment automatically, and pair both with a clear remediation process so that findings get fixed rather than archived in a folder nobody reopens. Make sure the testing scope explicitly covers the cloud-hosted services your remote staff use day to day, not just the legacy on-premise estate. If you have not requested a penetration test quote for external testing in the past six months, it is worth doing now. Yesterday’s clean report says nothing about today’s attack surface, and the surface keeps moving with every new project.
About The Author
