tools

Overview

Burp Proxy intercepts all HTTP and HTTPS traffic between a browser and the back-end server, allowing real-time examination and modification of requests and responses. It is the entry point for all Burp Suite workflows — traffic captured here is forwarded to Repeater, Intruder, or Scanner.

Target / Context

Any web application. Used during active web penetration testing to intercept, manipulate, and replay HTTP/HTTPS traffic.

Installation

ℹ︎Installation Commands:

Part of Burp Suite — see Burp Suite for installation.

Basic Usage

ℹ︎Basic Usage:
  1. Launch Burp Suite — proxy listener starts on 127.0.0.1:8080 by default
  2. Configure browser to route traffic through the proxy (see use cases below)
  3. Enable interception: Proxy tab → Intercept → toggle On
  4. Browse the target — requests are held until forwarded or dropped

Flags & Options

ℹ︎Proxy Listener Settings:

Proxy → Proxy Settings → Proxy Listeners

SettingDescription
Listener portDefault 8080 — change to any available port if needed
Bind to loopback onlyDefault — use 0.0.0.0 to receive traffic from other hosts
Redirect to hostForces all traffic to a specific target regardless of Host header

Common Use Cases

Configure the Pre-Built Browser

Use Burp’s embedded Chromium browser — no proxy configuration or certificate installation required.

ℹ︎Steps:

Proxy tab → Intercept → Open Browser

Configure FoxyProxy (Real Browser)

Route a real Firefox instance through Burp. Recommended over manual proxy settings.

ℹ︎Steps:
  1. Install the FoxyProxy extension in Firefox
  2. Open FoxyProxy → Options → Add
  3. IP: 127.0.0.1, Port: 8080 (match your configured listener port)
  4. Enable the proxy entry in FoxyProxy

Install the CA Certificate (HTTPS)

Required for HTTPS interception when using a real browser. Without it, HTTPS traffic fails or triggers browser certificate warnings on every request.

ℹ︎Steps:
  1. With Burp running and the browser proxied, navigate to http://burp
  2. Click “CA Certificate” to download the cert
  3. Firefox: about:preferences#privacy → View Certificates → Authorities tab → Import
  4. Check “Trust this CA to identify websites” → OK

Set Target Scope

Limit Burp to only process traffic matching your target — reduces noise from browser background requests.

ℹ︎Steps:
  1. Target tab → Site Map → right-click the target host → Add to Scope
  2. Proxy → Proxy Settings → under interception rules, select “and URL is in target scope” To exclude specific paths (e.g., logout): right-click the path → Remove from Scope

Intercept and Modify a Request

Hold a request before it reaches the server, make changes, then forward it.

ℹ︎Steps:
  1. Proxy tab → Intercept → toggle On
  2. Browse to trigger the request — it is held in the Intercept pane
  3. Edit headers, parameters, or body content as needed
  4. Forward (send as-is), Drop (discard), or CTRL+R to send to Repeater

Intercept Responses

Modify the server’s response before the browser renders it. Useful for enabling disabled form fields, revealing hidden inputs, or bypassing client-side validation.

ℹ︎Steps:
  1. Proxy → Proxy Settings → Response Interception Rules → enable “Intercept responses”
  2. After forwarding a request, the response is held for editing Example: change type=“number” to type=“text” to allow arbitrary text in a numeric field

Persistent Automatic Response Modification

Apply the same response transformation on every matching response without manual interception each time.

ℹ︎Steps:

Proxy → Proxy Settings → HTTP Match and Replace Rules → Add

FieldValue
TypeResponse Body
Matchtype=“number”
Replacetype=“text”
Regex MatchFalse

Match and Replace (Requests)

Automatically transform outgoing request headers or body content on every request.

ℹ︎Example — Override User-Agent:

Proxy → Proxy Settings → HTTP Match and Replace Rules → Add

FieldValue
TypeRequest Header
Match^User-Agent.*$
ReplaceUser-Agent: HackTheBox Agent 1.0
Regex MatchTrue

View HTTP History

All captured requests and responses are logged in Proxy → HTTP History. If a request was modified, the pane header reads “Original Request” — click it to toggle between original and edited versions.

Both HTTP history and WebSockets history are maintained. WebSockets history shows asynchronous updates and data-fetch requests that fire after the initial page load, which is useful during advanced web testing.

Proxy External CLI Tools Through Burp

Route command-line tool traffic through Burp to inspect and modify it alongside browser traffic.

ℹ︎Proxychains:

Edit /etc/proxychains4.conf — comment out the existing socks4 line and add:

http 127.0.0.1 8080

Run any command through proxychains:

proxychains -q <command>

The -q flag suppresses proxychains’ connection output from the terminal.

ℹ︎Metasploit Module:

Inside a Metasploit module’s options:

set PROXIES HTTP:127.0.0.1:8080

References / Images