What type of attacks does a web application firewall (WAF) guard against?

A web application firewall (WAF) is specifically designed to protect web applications by filtering and monitoring HTTP traffic between a web application and the internet. The primary purpose of a WAF is to guard against application-level attacks, which include SQL injection and cross-site scripting (XSS).

SQL injection attacks occur when an attacker is able to manipulate a web application's database by injecting malicious SQL statements into input fields, leading to unauthorized access to data. A WAF can identify and block these types of attempts by analyzing the incoming requests for malicious patterns.

Similarly, cross-site scripting (XSS) attacks involve injecting malicious scripts into web pages that are viewed by other users. These scripts can steal cookies, session tokens, or other sensitive information. A WAF can help prevent these attacks by inspecting the web traffic and ensuring that any harmful scripts do not get executed in the user's browser.

While the other types of attacks listed—malware infections, denial of service (DoS), and phishing attempts—are significant threats within the cybersecurity landscape, they fall outside the specific scope of protection that a WAF provides. Malware infections typically involve endpoints or files rather than web traffic analysis, while DoS attacks focus on overwhelming resources and are better mitigated by network-based defenses.