The Most Common Network Security Vulnerabilities

Most network compromises don't require advanced techniques. They take advantage of familiar weaknesses that are easy to overlook. Here are the issues that show up most often, and what to do about each.

Unpatched systems

Servers, firewalls and network devices running outdated software may carry known, publicly documented vulnerabilities. Keep an inventory of devices and a regular patch schedule.

Default or weak credentials

Routers, printers, cameras and management interfaces often ship with default passwords. Change them, and use strong, unique credentials for every device.

Exposed services

Remote desktop, file shares and admin panels reachable directly from the internet are frequent entry points. Put them behind a VPN or zero-trust access, or remove them.

Flat networks

When every device can reach every other device, one compromised laptop can reach your servers. Segment the network so critical systems are isolated.

Misconfigured firewalls

Overly broad allow rules and forgotten exceptions wear down your protection. Review firewall rules regularly and remove what is no longer needed.

Insecure Wi-Fi

Weak passphrases, outdated encryption and guests on the business network expose internal systems. Use WPA3 or WPA2 with a strong passphrase and a separate guest network.

Outdated protocols

Older protocols such as SMBv1, Telnet and unencrypted FTP lack modern protections. Disable them and switch to secure alternatives.

Limited visibility

Without logging and monitoring, attacks can go unnoticed for a long time. Collect logs from key systems and make sure someone reviews the alerts.

Finding your own weak spots

A vulnerability assessment or penetration test shows which of these issues exist in your environment and which matter most.