A URL, or Uniform Resource Locator, is the web address that points to a resource online. It tells a browser where to go and often includes the scheme, domain, path, and sometimes query parameters that add extra instructions or data. In security work, URLs matter because they can reveal where traffic is headed and what information is being carried along with a link.
Attackers use URLs in phishing emails, malicious ads, and fake login pages to lure people to harmful sites, often hiding suspicious destinations behind shortened links or lookalike domains. Defenders inspect URLs to block known-bad domains, strip tracking parameters, and spot unusual patterns before a link is shared. A URL may look like a simple address, but it can also carry identifiers that affect privacy and security.