Offensive security assessments
How to Identify DOM-Based XSS?
DOM-based XSS occurs when the vulnerability is in the JavaScript code running in the browser, rather than in the server-side response. The malicious script is executed purely on the client side without the server modifying the page.
Why it matters
DOM-based XSS occurs when the vulnerability is in the JavaScript code running in the browser, rather than in the server-side response. The malicious script is executed purely on the client side without the server modifying the page. How This XSS is DOM-Based
How we test it
Our operators follow a structured checklist for this topic, adapted to your API surface and authentication model.
Testing approach
- Open DevTools (F12 → Sources tab).
- Search (Ctrl + F) for location.search, innerHTML, or other sources/sinks.
- Open DevTools Console and run:
- If location is modified dynamically, it may be vulnerable.
- Chrome/Firefox "DOM XSS Scanner" extensions can help detect vulnerabilities.
- Can automatically detect and test for DOM XSS.
- This retrieves everything after the ? in the URL.
- Example: If the URL is:
What we look for
- Open DevTools (F12 → Sources tab).
- Search (Ctrl + F) for location.search, innerHTML, or other sources/sinks.
- Open DevTools Console and run:
- If location is modified dynamically, it may be vulnerable.
- Chrome/Firefox "DOM XSS Scanner" extensions can help detect vulnerabilities.
- Can automatically detect and test for DOM XSS.
- This retrieves everything after the ? in the URL.
- Example: If the URL is:
Related topics
| Topic | Summary |
|---|---|
| XSS - Cross Site Scripting | XSS is exploited when the attacker can successfully execute any type of script (for example, JavaScript) on the victim's browser. These types of flaws exist because the developer did not validate the request or correctly encoded the response of the application. JavaScript is not… |