threat-modeling.md

Threat Model Analysis for fatedier/frp

Threat: Unsecured frps Instance

• Description: Attacker attempts to connect to the frps server using default or weak credentials (e.g., default admin password). If successful, they can access the frps admin panel or directly establish tunnels to the internal network.
• Impact: Unauthorized access to internal services, data breaches, potential for lateral movement within the internal network.
• Affected frp component: frps (Admin Panel, Authentication Module)
• Risk Severity: High
• Mitigation Strategies:
  • Change default admin_user and admin_passwd.
  • Disable or restrict access to the admin_addr and admin_port if not needed.
  • Implement strong authentication mechanisms for frps admin panel (if enabled).
  • Use network firewalls to restrict access to the frps admin port.

Threat: frps Software Vulnerabilities

• Description: Attacker exploits known or zero-day vulnerabilities in the frps binary. This could involve sending crafted network packets or exploiting weaknesses in the frps code.
• Impact: Server compromise, denial of service, remote code execution, potential for attackers to gain control of the frps server and pivot to connected clients or backend services.
• Affected frp component: frps (Core Binary, Network Handling, Protocol Parsing)
• Risk Severity: Critical to High (depending on vulnerability type)
• Mitigation Strategies:
  • Keep frps server updated to the latest version with security patches.
  • Implement intrusion detection/prevention systems (IDS/IPS) to detect malicious traffic.
  • Follow security best practices for server hardening.
  • Consider using a Web Application Firewall (WAF) if frps is exposing web services.

Threat: Man-in-the-Middle (MitM) Attacks on frps Communication

• Description: Attacker intercepts communication between frpc and frps if tunnels are not properly encrypted or use weak encryption. This can be done by network sniffing or ARP poisoning.
• Impact: Data interception, credential theft, potential for attackers to inject malicious data or commands into the communication stream, compromising data confidentiality and integrity.
• Affected frp component: frps & frpc (Tunnel Communication, Encryption Modules)
• Risk Severity: High
• Mitigation Strategies:
  • Always use encrypted tunnel protocols like stcp or xtcp for sensitive data.
  • Enforce strong TLS configurations for encrypted tunnels (strong cipher suites, up-to-date TLS versions).
  • Ensure proper certificate validation if using TLS with certificates.
  • Use network segmentation to limit the attacker's ability to intercept traffic.

Threat: Compromised frpc Host

• Description: If the machine running frpc is compromised through other vulnerabilities (unrelated to frp itself), attackers can leverage the existing frpc connection to access internal services exposed through frp tunnels. While the initial compromise is not directly frp related, the exploitation of the frp tunnel is a direct consequence of using frp.
• Impact: Unauthorized access to internal network and services, data breaches, lateral movement within the internal network, bypassing intended security controls.
• Affected frp component: frpc (Client Host Environment, Tunnel Access)
• Risk Severity: Critical
• Mitigation Strategies:
  • Harden the frpc client host operating system and applications.
  • Implement strong access controls and least privilege principles on the frpc client host.
  • Regularly patch and update the frpc client host operating system and applications.
  • Use endpoint detection and response (EDR) solutions on the frpc client host.
  • Network segmentation to limit the impact of a compromised frpc host.

Threat: frpc Software Vulnerabilities

• Description: Attacker exploits known or zero-day vulnerabilities in the frpc binary. This could involve malicious responses from the frps server or crafted network packets.
• Impact: Client compromise, remote code execution on the frpc client machine, potential for attackers to gain control of the frpc client and pivot to the frps server or internal network.
• Affected frp component: frpc (Core Binary, Network Handling, Protocol Parsing)
• Risk Severity: Critical to High (depending on vulnerability type)
• Mitigation Strategies:
  • Keep frpc clients updated to the latest version with security patches.
  • Implement host-based intrusion detection systems (HIDS) on frpc client machines.
  • Follow security best practices for client host hardening.

Threat: Insecure Tunnel Protocols

• Description: Using insecure tunnel protocols like plain tcp for sensitive data without proper encryption. Attackers intercept network traffic on the path between frpc and frps.
• Impact: Data interception, credential theft, exposure of sensitive information transmitted through the tunnel, compromising data confidentiality.
• Affected frp component: frps & frpc (Tunnel Protocol Selection, Communication Channels)
• Risk Severity: High
• Mitigation Strategies:
  • Avoid using plain tcp tunnels for sensitive data.
  • Always use encrypted tunnel protocols like stcp or xtcp for sensitive data.
  • Educate developers and operators about secure tunnel protocol selection.

Threat: Insecure Storage of Credentials (Operational)

• Description: Storing authentication credentials (e.g., auth_token, admin_user, admin_passwd) in plain text or insecurely in operational processes (scripts, configuration management).
• Impact: Unauthorized access to frps server, potential for attackers to establish unauthorized tunnels and access internal services, credential theft.
• Affected frp component: Operational Processes, Credential Management (Impacting frp security)
• Risk Severity: High
• Mitigation Strategies:
  • Use secure credential management practices.
  • Avoid hardcoding credentials in scripts or configuration files.
  • Use environment variables or dedicated secrets management solutions to store and retrieve credentials.
  • Implement access control to credential storage locations.

Threat: Failure to Patch and Update

• Description: Not regularly updating frps and frpc binaries to the latest versions. This leaves them vulnerable to known security vulnerabilities.
• Impact: Exploitation of known vulnerabilities, server and client compromise, potential for wider network compromise, increased attack surface.
• Affected frp component: frps & frpc (Core Binaries, Software Update Process)
• Risk Severity: High to Critical (depending on vulnerability severity)
• Mitigation Strategies:
  • Establish a regular patching and update schedule for frps and frpc.
  • Monitor security advisories and vulnerability databases for frp.
  • Automate the update process if possible.
  • Test updates in a non-production environment before deploying to production.