Burp Proxy Rotate

Burp Proxy Rotate is a Burp Suite extension that routes each HTTP request through a random proxy from a configurable list. Each new connection from Burp is assigned a proxy, enabling IP rotation for better anonymity, WAF evasion, geo-targeted testing, and other advanced use cases. This ensures requests exit through different IPs and can help simulate distributed attack patterns during security assessments.

Author

Petru Surugiu <@pedro_infosec>

Key Features

• Advanced Proxy Rotation: Leverages Java NIO for non-blocking, event-driven proxying, assigning a different proxy node on a per-connection basis.
• Multiple Protocol Support:
  • SOCKS5: Full support, including username/password authentication.
  • SOCKS4 & SOCKS4a: Full support.
  • HTTP Proxies: Supports HTTP CONNECT tunneling, including Basic authentication.
  • Direct Connections: Ability to bypass proxies for specified domains (e.g., Burp Collaborator).
• Authentication: Supports SOCKS5 username/password and HTTP Basic proxy authentication.
• Support for Bypass Domains:
  • Pre-configured to bypass Burp Collaborator domains (burpcollaborator.net, oastify.com).
  • Supports adding custom domains to the bypass list.
• Proxy List:
  • Add proxies individually or in bulk.
  • Formats supported: protocol://host:port and protocol://user:pass@host:port.
  • Validate individual or all proxies to exclude unresponsive proxies.
  • Easy to manage the proxy list through the UI.
• Internal Proxy Service Control:
  • Configure local listening port (manual or random).
  • Adjust buffer sizes, idle timeouts, and maximum connections per proxy.
  • Choose between "Round-Robin" or "Random" proxy selection strategies.
• Detailed Logging & Status: Real-time logging and connection statistics.

Technical Architecture & Performance

Burp Proxy Rotate is designed for stability and speed, utilizing modern Java features:

• Core Engine (ProxyRotateService):
  • Java NIO (Non-blocking I/O): Built around a java.nio.channels.Selector for managing many concurrent connections with a single thread, minimizing overhead.
  • Event-Driven: Handles network events (accept, connect, read, write) asynchronously.
  • Connection State Management: Each client-to-proxy-to-target pipeline is managed by a ConnectionState object, tracking the current stage (e.g., SOCKS handshake, HTTP CONNECT, data relay).
  • Protocol Handling: Implements SOCKS4/SOCKS5 and HTTP CONNECT handshake logic.
• Buffer Management:
  • Direct ByteBuffers: Used for I/O operations to potentially reduce copying between JVM heap and native memory.
  • Adaptive Buffer Sizing: Starts with a default buffer size (configurable, 8KB default) and dynamically increases capacity for specific connections (e.g., 128KB-256KB for HTTP/Direct/HTTPS) to handle larger data chunks like HTTP headers or TLS records efficiently.
• Socket Optimizations:
  • TCP_NODELAY: Enabled to disable Nagle's algorithm, reducing latency for small, frequent packets.
  • SO_REUSEADDR: Enabled on the server socket.
  • Socket keepAlive is enabled for client connections.
  • Performance preferences (setPerformancePreferences(0, 1, 0)) are set for direct connections to prioritize latency.
• Thread Management:
  • Dedicated, prioritized selector thread for network I/O.
  • Scheduled executor for periodic idle connection cleanup and enforcing rotation.
  • Thread pool for concurrent proxy validation.
• Resilience:
  • Proxy Failure: Notifies the UI if an upstream proxy fails during connection establishment.
  • Direct Connection Fallback: If a direct connection to a bypass domain fails, it can attempt to route through a standard proxy.
  • JDK Epoll Bug Workaround: Includes logic to recreate the selector in case of a known JDK bug related to epoll_wait returning 0 indefinitely.

Screenshots

Main Tab

Settings

Demo

How to Use

1. Install/Build:
   • Grab a precompiled JAR from build/libs folder. -> burp-proxy-rotate.jar
   • OR build the extension using (./gradlew build).
   • In Burp Suite, go to Extensions -> Installed -> Add and select the JAR file.
2. Configure Proxies:
   • Navigate to the "Proxy Rotate" tab in Burp Suite.
   • Use the "Single Proxy" or "Bulk Add" options to add your SOCKS4, SOCKS5, or HTTP proxies.
     • Format: protocol://host:port (e.g., socks5://127.0.0.1:1080)
     • Authenticated Format: protocol://username:password@host:port (e.g., http://user:pass@proxy.example.com:8080)
3. Validate Proxies (Recommended):
   • Click "Validate All" to check the status of your added proxies. Inactive or problematic proxies will be indicated and excluded.
4. Enable Extension
   • Click "Enable Proxy Rotate". The status will update to "Running on 127.0.0.1:PORT".
   • Configure the "Local port" if needed (or use random port -- recommended).

User Interface Guide

The extension provides a user-friendly interface with two main tabs:

Main Tab

• Local Port: Configure the port on localhost where the Proxy Rotate service will listen. Can be set to a specific port or "Random Port" (default option and recommended).
• Service Control:
  • Enable Proxy Rotate: Enables the extension and starts the local proxy service.
  • Disable Proxy Rotate: Disables the extension and stops the local proxy service.
• Status & Stats:
  • Status: Shows if the service is "Stopped", "Running on 127.0.0.1:PORT", or "Failed to start".
  • Stats: Displays the number of active connections and details about proxy utilization (e.g., "Active connections: 5 | Using 3 proxies, busiest: ...").
• Proxy List Table: Displays your configured upstream proxies with columns for:
  • Protocol: (socks4, socks5, http)
  • Host: Proxy host.
  • Port: Proxy port.
  • Auth: "Yes" if credentials are provided, "No" otherwise.
  • Status: "Active", "Inactive", or "Validating..." with any error messages.
• Proxy Management Buttons:
  • Remove Selected: Removes the highlighted proxy from the list.
  • Clear All: Removes all proxies from the list (with confirmation).
  • Validate All: Initiates a health check for all proxies in the list.
• Proxy Addition Tabs:
  • Single Proxy: Add one proxy at a time using the URL format.
  • Bulk Add: Paste multiple proxy URLs (one per line).

Settings Tab

• Connection Settings:
  • Buffer Size (bytes): Default read/write buffer size for new connections (default: 8192 bytes). Adaptive sizing increases this for HTTP/direct connections.
  • Idle Timeout (sec): Time after which an inactive connection is closed (default: 60 seconds). A shorter, internal "moderately idle" timeout (10s) also helps enforce rotation.
  • Max Connections Per Proxy: (Currently informational in ProxyRotateService but not strictly enforced as a hard limit by the service in terms of rejecting new connections beyond this count per proxy).
• Enable Logging: Toggles detailed logging to the Burp Extensions output and the Log panel in the UI.
• Bypass Collaborator: If checked, attempts to connect directly to known Burp Collaborator domains, bypassing upstream proxies.
• Proxy Selection Mode:
  • Round-Robin: Selects proxies sequentially from the active list.
  • Random: Selects a random proxy from the active list for each new connection.
• Bypass Domains (one per line): Manage a list of domains that should be connected to directly, bypassing the proxy list. Default entries include burpcollaborator.net and oastify.com.
• Reset to Default Settings: Resets all settings in this tab to their original default values.

Log Panel (Bottom of Main Tab)

• Displays real-time logs from the extension, including connection attempts, proxy selections, errors, and status changes.

Changelog

See full changelog CHANGELOG.