1. Web Security Academy
  2. DOM-based
  3. Link manipulation

DOM-based link manipulation

In this section, we'll talk about what DOM-based link manipulation is, look at the impact of an attack, and suggest ways of preventing them.

DOM-based link-manipulation vulnerabilities arise when a script writes attacker-controllable data to a navigation target within the current page, such as a clickable link or the submission URL of a form. An attacker might be able to use this vulnerability to construct a URL that, if visited by another application user, will modify the target of links within the response.

An attacker may be able to leverage this vulnerability to perform various attacks, including:

  • Causing the user to be redirected to an arbitrary external URL, which could facilitate a phishing attack.
  • Causing the user to submit sensitive form data to a server controlled by the attacker.
  • Changing the file or query string associated with a link, causing the user to perform an unintended action within the application.
  • Bypassing browser anti-XSS defenses by injecting on-site links containing XSS exploits. This works because anti-XSS defenses do not typically account for on-site links.

The following are some of the main sinks can lead to DOM-based link-manipulation vulnerabilities:

someDOMElement.href
someDOMElement.src
someDOMElement.action

In addition to the general measures described on the DOM-based vulnerabilities page, you should avoid allowing data from any untrusted source to dynamically set the target URL for links or forms.