This blog was originally published on December 8, 2025
A laptop missed a routine security update and stayed connected to a law firm’s network for months. It ran normally, connected normally, and gave no sign that a known flaw in its operating system had already been fixed on every other device on that network.
The update that should have been installed on that laptop never was. That single miss is close to the definition of a network security vulnerability, a weakness in a system, a configuration, or a process. A threat is what exploits it, whether that is a targeted attacker or an automated scan working through known flaws. Common network security threats often need nothing more than an unpatched laptop to find a way in.
Common network security vulnerabilities to know about
Four vulnerabilities show up across professional services firms more than any others. Each starts the same way. Something is left in an unintended state, and someone eventually finds it.
Unpatched software and devices
An unpatched vulnerability is a flaw or weakness for which a fix exists but has not yet been applied. Vendors release updates when they find a flaw in their own code, and those updates close whatever openings the flaw created. Once a vendor publishes a fix, the flaw becomes public knowledge too, and attackers know that many businesses will not apply it right away. CISA’s guidance on keeping business software updated warns that criminals actively exploit out-of-date software, and once a patch is public, the weakness it fixes can remain useful to attackers for as long as it takes businesses to install it. A single laptop, an old server, or a piece of forgotten network hardware is enough to leave that opening in place for an attacker to use.
Weak access controls
Access controls decide who can reach what inside a business, and weaknesses here tend to compound. A password reused across several systems means one leaked credential unlocks all of them. An account that keeps more access than someone’s role requires becomes a wider target than necessary, and accounts that stay active after an employee changes role or leaves the firm add exposure that goes unnoticed. CISA lists requiring multi-factor authentication among the most effective defenses here, since it stops a stolen password from being enough on its own to reach an account.
Unsecured or unmanaged endpoints
An endpoint is any device connected to a business network, such as a laptop, desktop computer, or work phone. Each one needs to be patched and monitored to the same standard as the servers behind it. A laptop used for both work and personal browsing, or a phone that syncs company email without any security software installed, can give an attacker a foothold that spreads beyond the device itself.
Misconfigured remote access
Remote access exists so employees can reach company systems from outside the office, and most firms depend on it. Problems appear when the configuration around it falls behind the need for it. A remote access tool installed years ago and never removed, or a service left reachable from the open internet without the authentication it needs, gives an attacker a way in that the firm may not know exists. The same is true of access left active for someone who no longer works there. Ordinary use will not reveal weaknesses like these. A closer look, described next, will.
How a network vulnerability assessment finds these weaknesses
A system that runs without any visible problem can still carry the weaknesses already described. Normal performance is not the same as security, and there is no way to know which one you have without looking closely. A network vulnerability assessment is built for that kind of look. It reviews the environment for missing updates and exposed services, then checks configurations and access against what they should be, flagging whatever needs closer investigation. The result is a structured view of where weaknesses sit and which ones deserve attention first, instead of a broad assumption that nothing is wrong. BASE Solutions runs a Cyber Risk Assessment along these lines, giving a business that view before a weakness turns into something bigger.
Why network security vulnerabilities affect cyber insurance
Cyber insurers ask about these same weaknesses before issuing or renewing a policy. Applications and renewal questionnaires commonly cover multi-factor authentication, how fast known vulnerabilities get patched, how remote access is secured, and any vulnerability assessment work already in place, according to underwriting resources compiled by Indiana’s state cybersecurity office. Requirements differ by insurer, and one control in place does not guarantee coverage any more than one missing control guarantees a claim will be refused. What has changed is that these weaknesses, once treated as a technical detail for someone else to manage, now factor into how a business demonstrates its cyber hygiene to underwriters. Cyber Hygiene, Properly looks at the practices that keep a policy’s terms intact, and a recent account of a DMV business’s near-miss with a cyber insurance claim shows how directly these weaknesses can affect that outcome.
How to reduce network security vulnerabilities
A repeatable process for finding these weaknesses does more for a firm than solving every one of them at once.
Patching works best as a scheduled routine. Leaving it to individual employees to remember is how devices get missed in the first place. Access deserves the same routine treatment. A periodic review should cover who has access and what that access allows, checked against how well it still fits the role a person holds. This carries the most weight whenever someone’s access needs change, most obviously when they leave the firm. Endpoints need consistent management. Handling them case by case leaves some unpatched for long stretches. Remote access earns a place in the same review cycle, with old tools retired and what remains limited to people who still need it. Ongoing monitoring closes the loop, catching a login at an unusual hour or traffic heading somewhere it should not, the kind of activity that would otherwise pass unnoticed between reviews.
A clear, verified picture of which weaknesses sit inside a network and which ones deserve attention first counts for more than mastering every technique behind common network security threats. A general sense that things are probably fine will not provide that picture. Looking closely will, and so will knowing what to address before someone outside the firm finds it first.
That laptop from the opening example ran for months before anyone noticed. BASE Solutions’ Cyber Risk Assessment is built to catch that kind of thing sooner, then rank it by what needs fixing first.
