If you’ve never had an internal vulnerability scan done, the concept can feel abstract. What does it actually look at? What kind of problems does it find? And what do you do with the results?
Let’s demystify it. Here’s what an internal vulnerability scan actually does, what typical findings look like, and why it’s one of the most valuable things you can do for your security posture.
What an Internal Vulnerability Scan Is
An internal vulnerability scan is an automated assessment of the systems inside your network. Unlike an external scan (which looks at what’s exposed to the internet), an internal scan evaluates what an attacker would see if they were already inside your network, or what a malicious insider could access.
The scanner connects to your internal network and systematically checks hosts, servers, workstations, and network devices for known vulnerabilities, misconfigurations, and security weaknesses.
It’s not a penetration test; it doesn’t try to exploit what it finds. It identifies and catalogs vulnerabilities so you can prioritize and fix them before someone else finds them.
What It Typically Finds
Every environment is different, but certain categories of findings show up in nearly every internal scan. Here’s what to expect.
Missing Patches
This is almost always the biggest category. Operating systems, applications, and firmware that haven’t been updated contain known vulnerabilities, many of which have public exploits available.
Common examples:
- Windows servers missing critical security updates
- Outdated versions of software like Java, Adobe, or web browsers
- Network device firmware that hasn’t been updated in years
- Database servers running versions past end-of-life
Missing patches are straightforward to fix but easy to overlook, especially in environments without a formal patch management process.
Weak or Default Configurations
Systems often ship with default settings that prioritize ease of use over security. If those defaults were never hardened, they become vulnerabilities.
Common examples:
- Default credentials on network devices, printers, or management interfaces
- Services running with unnecessary privileges
- Unnecessary ports and services exposed
- Weak encryption protocols still enabled (SSL 3.0, TLS 1.0, weak cipher suites)
- SNMP using default community strings like “public” or “private”
These findings are common in environments where systems were deployed and never security-hardened.
End-of-Life Software
Software that’s no longer supported by the vendor no longer receives security updates. Running it means known vulnerabilities will never be patched.
Common examples:
- Windows Server 2012/2012 R2 (end of extended support)
- Older versions of SQL Server, Exchange, or Linux distributions
- Legacy applications that depend on outdated frameworks
- Network devices running firmware the vendor no longer supports
End-of-life findings require a plan, either upgrade, migrate, or implement compensating controls.
Certificate and Encryption Issues
Internal services often use self-signed, expired, or weakly configured certificates. While these might not seem critical on an internal network, they can enable man-in-the-middle attacks and indicate broader security hygiene issues.
Common examples:
- Expired SSL/TLS certificates on internal web applications
- Self-signed certificates with no internal CA
- Services using deprecated protocols (TLS 1.0/1.1)
- Weak key sizes (1024-bit RSA)
Network Segmentation Gaps
A scan sometimes reveals that systems can communicate with each other when they shouldn’t be able to. Flat networks, where everything can talk to everything, amplify the impact of any single compromise.
Common examples:
- Workstations with direct access to database servers
- Guest Wi-Fi on the same network segment as production systems
- No separation between development and production environments
What the Results Look Like
A well-run vulnerability scan produces a report organized by severity:
| Severity | What It Means | Typical Action |
|---|---|---|
| Critical | Actively exploitable, high impact | Fix immediately |
| High | Exploitable with significant risk | Fix within 30 days |
| Medium | Represents real risk, lower exploitability | Fix within 90 days |
| Low | Minor risk, best practice improvements | Address during normal maintenance |
| Informational | Not a vulnerability, but worth noting | Review and document |
Each finding includes a description of the vulnerability, which hosts are affected, and recommended remediation steps. The best reports also include context, not just what’s wrong, but what it means for your business and what to prioritize.
Common Questions
“Will it break anything?”
A properly configured vulnerability scan is non-intrusive. It’s identifying vulnerabilities, not exploiting them. That said, it’s good practice to schedule scans during maintenance windows and coordinate with your IT team, especially the first time.
“How often should we scan?”
At minimum, quarterly. Monthly is better. The idea is to catch new vulnerabilities as they emerge, not just the ones that existed when you last looked.
“Can we do this ourselves?”
You can. Tools like Nessus, OpenVAS, and Qualys all offer scanning capabilities. The challenge for most small businesses isn’t running the scan; it’s interpreting the results, filtering out false positives, and building an actionable remediation plan. That’s where having an experienced set of eyes on the results makes a real difference.
“What do we do with the results?”
Prioritize and remediate. Start with critical and high findings, work your way down. Track your progress over time. Each subsequent scan should show improvement; that’s how you know your security posture is getting stronger.
The Bottom Line
An internal vulnerability scan shows you what’s actually happening inside your network, not what you think is happening. It’s one of the most practical, cost-effective security activities any business can do, and the findings almost always include things nobody knew about.
If you’ve never had an internal scan done, the results will give you a clear and prioritized list of things to fix. If you’ve had one before, regular scanning keeps you on track and catches new issues before they become problems.
We provide internal vulnerability scans with clear, actionable reporting, not just a raw data dump, but findings with context, priorities, and remediation guidance tailored to your environment.
– Derek, Founder of DC Security Solutions.
DC Security Solutions provides internal vulnerability scanning with actionable remediation guidance. Learn more →