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10 Critical Network Pentest Findings IT Teams Overlook. After conducting over 10,000 automated internal network penetration tests last year, vPenTest has uncovered a troubling reality that many businesses still have critical security gaps that attackers can easily exploit. Organizations often assume that firewalls, endpoint protection, and SIEMs are enough to keep them secure. But how effective are these defenses when put to the test? That's where vPenTest, Vonahi Security's automated network pentesting platform, comes in. Designed to simulate real-world attack scenarios, vPenTest helps organizations find exploitable vulnerabilities before cybercriminals can. These aren't complex, zero-day exploits. They're misconfigurations, weak passwords, and unpatched vulnerabilities that attackers routinely exploit to gain access, move laterally, and escalate privileges within networks. Here's how these risks break down: In this article, we'll cover the ten most critical internal network security risks, breaking down what they are, why they're dangerous, and how to fix them before they turn into real problems. We'll start with the least common and work our way up to the number one issue we've seen across thousands of assessments with vPenTest. If these weaknesses exist in your environment, attackers will find them—it's just a matter of time. 10. Password Deficiencies - Redis Service CVSS3: 9.9 % of occurrence: 1.3% What is it: Security Impact: Recommendation: 9. Firebird Servers Accept Default Credentials CVSS3: 9.0 % of occurrence: 1.4% What is it: Security Impact: Recommendation: 8. Microsoft Windows RCE (BlueKeep) CVSS3: 9.8 % of occurrence: 4.4% What is it: Security Impact: Recommendation: 7. Microsoft Windows RCE (EternalBlue) CVSS3: 9.8 % of occurrence: 4.5% What is it: Security Impact: Recommendation: 6. IPMI Authentication Bypass CVSS3: 10.0 % of occurrence: 15.7% What is it: Security Impact: Recommendation: 5. Outdated Microsoft Windows Systems CVSS3: 9.8 % of occurrence: 24.9% What is it: Security Impact: Recommendation: 4. IPv6 DNS Spoofing CVSS3: 10.0 % of occurrence: 49.9% What is it: Security Impact: Recommendation: 3. Link-Local Multicast Name Resolution (LLMNR) Spoofing CVSS3: 9.8 % of occurrence: 65.5% What is it: Link-Local Multicast Name Resolution (LLMNR) is a protocol designed for name resolution within internal network environments when traditional Domain Name System (DNS) services are either unavailable or ineffective. LLMNR acts as a fallback mechanism, facilitating the resolution of DNS names through multicast queries. The resolution process unfolds as follows: This reliance on multicast broadcasts introduces vulnerabilities, as any active system can respond to the queries, potentially misleading the requesting system. Security Impact: Recommendation: 2. NetBIOS Name Service (NBNS) Spoofing CVSS3: 9.8 % of occurrence: 73.3% What it is: The NetBIOS Name Service (NBNS) is a protocol utilized by workstations within an internal network to resolve domain names when a DNS server is unavailable or unresponsive. When a system attempts to resolve a DNS name, it follows these steps: This dependency on broadcasts makes the NBNS vulnerable to spoofing attacks, wherein an attacker can respond with a false IP address. Security Impact: Recommendation: 1. Multicast DNS (mDNS) Spoofing CVSS3: 9.8 % of occurrence: 78.2% What it is: Multicast DNS (mDNS) serves as a name resolution protocol for local networks, facilitating the resolution of domain names when a dedicated DNS server is unavailable. The resolution process occurs in stages: Security Impact: Recommendation: What Pentesting Reveals About Security Gaps After analyzing tens of thousands of network assessments, one thing is clear—many security gaps aren't the result of advanced hacking techniques but simple, avoidable mistakes. Weak passwords, forgotten misconfigurations, and unpatched systems create easy opportunities for attackers. These aren't once-in-a-lifetime vulnerabilities. They're recurring problems that show up in networks of all sizes, year after year. Pentesting is like stress-testing your security before a real attacker does. It reveals how someone could break in, move around, and escalate privileges using the same tactics real-world attackers rely on. Time and again, assessments prove that even companies with strong defenses often have hidden weaknesses waiting to be exploited. The problem? Most organizations still rely on annual pentests for compliance, leaving months of blind spots in between. That's where vPenTest from Vonahi Security comes in. It delivers automated, on-demand network pentesting, so instead of waiting for an audit to tell you what went wrong, you can find and fix exploitable vulnerabilities year-round. Cyber threats aren't slowing down, so security testing shouldn't either. Whether done manually or through automation, regular network pentesting is the key to staying ahead of attackers—not just checking a box for compliance. Want to explore vPenTest and see the power of automated network pentesting for yourself? Schedule a free demo of vPenTest!