Reasons why firewalls do not give total security

Firewalls are a crucial component of network security, but they do not provide total security. Here are some reasons why:

• Firewalls are ineffective against insider threats. A firewall primarily protects the network perimeter from external attacks. It cannot prevent malicious activities or accidental data breaches initiated by authorized users within the network.
• Security relies heavily on correct configuration. Misconfigured firewall rules, due to human error, can unintentionally create vulnerabilities or open ports. This allows malicious traffic to bypass intended protections.
• Firewalls do not inherently protect against attacks exploiting vulnerabilities in applications or protocols permitted by the firewall. For instance, if a web server accessible through a firewall has a software vulnerability, the firewall will still allow valid HTTP/S traffic. It cannot prevent an attack that exploits a flaw within that legitimate traffic.
• Firewalls are generally ineffective against zero-day exploits. They operate based on known attack patterns or defined rules. Therefore, they cannot block attacks that leverage newly discovered vulnerabilities for which no signatures or patches exist yet.
• They cannot prevent threats that bypass the network perimeter entirely. Examples include threats introduced via physical access, like an infected USB drive, or through social engineering techniques that trick users into compromising security.