> For the complete documentation index, see [llms.txt](https://hacking-notes.jord4n.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hacking-notes.jord4n.pro/web/authentication/username-enumeration-via-response-timing.md).
# Username Enumeration via Response Timing
Username Enumeration via Response Timing notes for PortSwigger Web Security Academy labs, including exploitation workflow, payload testing, Burp Suite validation, and remediation context.
### Username Enumeration via Response Timing
This lab is vulnerable to user name enumeration based on response time. To resolve it, you need to identify a valid user name, perform a raw force attack on your password, and then access your account page.
```bash
Your credentials: wiener:peter
```
### **Initial Analysis**
When testing a large number of passwords, the application displays an error message indicating that an excessive number of attempts has been detected.
To circumvent this protection, the following header is added:
```bash
X-Forwarded-For: 127.0.0.2
```
### **Response Time Measurement**
Send a request with an extremely long **password** for user `wiener`:
{% code overflow="wrap" %}
```bash
username=wiener&password=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
```
{% endcode %}
It is then observed that the answer takes about **3 seconds** to arrive.
On the other hand, if the same request is sent with an invalid user name\*\*, the answer is **quasi instant**:
```bash
username=dwdwd&password=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
```
This difference therefore makes it possible to distinguish a valid **username** from a invalid.
#### **List with Intruder**
In Intruder, we use the **Pitchfork** technique.
* First position: list of **usernames** to be tested
Second position: list of **different IP addresses** sent to `X-Forwarded-For`
The field **response completed** is analyzed:
Responses associated with a valid user have significantly higher time (Apache indicates a much larger value).
This allows to identify the correct user.
#### \*\* Brute Password Strength\*\*
After finding the valid user name, you start the attack on your password.
We note that the attempt with the password **chelsea** produces a different answer: a **302 Found**, sign that authentication is successful.
Access to the account is then confirmed.
---
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