Availability / Denial of Service

Description

Denial of Service (DoS) is a type of IT vulnerability that is classified under Availability in the Common Weakness Enumeration (CWE) directory. DoS occurs when a malicious actor intentionally floods a network or system with an overwhelming amount of traffic, requests, or connections. This can cause the system to become overwhelmed, resulting in a loss of availability of services and resources. DoS attacks occur in Infrastructure and Web and API components. According to the Open Web Application Security Project (OWASP) Testing Guide, DoS attacks can also occur with malicious user input.

Risk

DoS attacks can cause significant disruption to businesses as they can result in a complete loss of availability of services and resources. This can lead to a significant financial loss due to a disruption in services and resources. Additionally, DoS attacks can also lead to a decrease in customer trust and satisfaction.

Solution

The best way to prevent DoS attacks is to implement proper network and system security measures. Network security measures such as firewalls, intrusion detection systems, and web application firewalls can be used to detect and prevent malicious traffic from entering the network or system. Additionally, system security measures such as rate limiting and access control lists can be used to limit the amount of traffic or requests that can enter the network or system.

Example

The following example shows a code snippet from a web application that is vulnerable to DoS attacks. The code does not contain any rate limiting or access control list that can limit the amount of requests the web application can receive.

<?php
$request = $_GET['request'];

$response = processRequest($request);

echo $response;
?>