Pystinger : Bypass Firewall For Traffic Forwarding Using Webshell

Pystinger is a Python-based tool that enables SOCKS4 proxying and port mapping through webshells. It can be integrated with Metasploit Framework, Viper, and Cobalt Strike to maintain online sessions.

Currently, it supports three proxy script types: PHP, JSP(X), and ASPX.

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Usage Overview

Imagine a scenario where:

• The target server is accessible at http://example.com:8080
• Its intranet IP is 192.168.3.11

Pystinger allows you to set up a SOCKS4 proxy or perform port mapping in this environment.

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SOCKS4 Proxy (Single Target)

1. Upload the relevant proxy.jsp (or PHP/ASPX equivalent) to the target.
   • Ensure it is accessible at http://example.com:8080/proxy.jsp
   • The page should return UTF-8 output
2. Deploy the pystinger server executable on the target (through AntSword or another method).
   • ⚠️ Do not run it directly, as this may cause TCP disconnections.
3. Run the pystinger client from your VPS, pointing it at the uploaded webshell.
   • This creates a SOCKS4a proxy locally, letting you tunnel traffic into the target’s intranet.

At this stage, the VPS will host a proxy on 127.0.0.1:60000 that forwards traffic securely through the target server.

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Cobalt Strike Beacon (Multi-Target)

For multi-host or lateral movement scenarios:

1. Upload and run the webshell & pystinger server on the target.
   • You can bind the server to a specific intranet IP (e.g., 192.168.3.11) or 0.0.0.0 for broader reach.
2. Launch the pystinger client on your VPS to create a proxy channel.
3. In Cobalt Strike, add a listener on the mapped port (e.g., 60020).
   • Payloads can then connect through the proxy, keeping the beacon online even when pivoting across different hosts.

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Custom Headers & Proxy Support

• If the webshell requires authentication or cookies, you can configure custom headers using the --header option. --header "Authorization: XXXXX, Cookie: YYYYY"
• If your environment requires an upstream proxy, you can chain connections with: --proxy "socks5:127.0.0.1:1081"

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Key Takeaways

• Pystinger is designed for covert tunneling and proxying in restricted environments.
• It supports multi-framework integration (Metasploit, Viper, Cobalt Strike).
• With custom headers and proxy chaining, it adapts to complex infrastructure setups.

⚠️ Disclaimer: Use only in authorized penetration testing or red team engagements. Unauthorized use is illegal and unethical.

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🔗 References:

• Pystinger GitHub Project
• Kali Linux Tutorials Article