threat-modeling.md

Threat Model Analysis for twitter/twemproxy

Threat: Request Smuggling/Injection via Protocol Vulnerabilities

• Description: Attacker crafts malicious requests that exploit vulnerabilities in Twemproxy's memcached or Redis protocol handling. This could lead to command injection into backend servers, bypassing intended routing, or causing unexpected behavior within Twemproxy itself.
  • Impact: Backend server compromise, data manipulation, denial of service, potential for arbitrary code execution within Twemproxy (depending on vulnerability).
  • Affected Component: Protocol parsing module (memcached/Redis protocol handling), request routing logic.
  • Risk Severity: High to Critical (depending on the specific vulnerability)
  • Mitigation Strategies:
    • Keep Twemproxy updated to the latest version to patch known protocol handling vulnerabilities.
    • Perform security testing, including fuzzing, on Twemproxy's protocol handling.
    • Implement input validation and sanitization at the application level before data reaches Twemproxy.

Threat: Resource Exhaustion Denial of Service (DoS)

• Description: Attacker floods Twemproxy with a high volume of requests, legitimate or malicious, overwhelming its resources (CPU, memory, network bandwidth). This causes Twemproxy to become unresponsive and unable to serve legitimate traffic, leading to application downtime.
  • Impact: Denial of service, application unavailability, performance degradation for legitimate users.
  • Affected Component: Core Twemproxy process, network handling, request processing.
  • Risk Severity: High
  • Mitigation Strategies:
    • Implement rate limiting and traffic shaping in front of Twemproxy (e.g., using load balancers, firewalls, or web application firewalls).
    • Monitor Twemproxy resource utilization and set up alerts for abnormal spikes.
    • Configure connection limits and request queue management within Twemproxy if available and applicable.
    • Employ DDoS mitigation services if facing external threats.

Threat: Compromised Twemproxy Binary/Package Deployment

• Description: Attacker compromises the Twemproxy binaries or packages used for deployment, injecting malware or backdoors. Deploying a compromised Twemproxy instance allows the attacker to gain control over the proxy and potentially the backend systems and application data.
  • Impact: Full system compromise, data breach, data manipulation, denial of service, long-term persistent access for the attacker.
  • Affected Component: Twemproxy deployment process, software supply chain.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Download Twemproxy from official and trusted sources only (e.g., GitHub releases).
    • Verify the integrity of downloaded binaries using checksums or digital signatures.
    • Implement secure software supply chain practices, including code signing and secure build pipelines.
    • Regularly scan deployed Twemproxy instances for malware and anomalies.

Threat: Unencrypted Communication Interception

• Description: Attacker intercepts network traffic between clients and Twemproxy, or between Twemproxy and backend servers, because TLS/SSL encryption is not used. The attacker can passively monitor traffic to steal sensitive cached data or actively inject malicious data.
  • Impact: Data breach, information disclosure, potential data manipulation if active interception is possible.
  • Affected Component: Network communication channels, client-to-Twemproxy and Twemproxy-to-backend connections.
  • Risk Severity: High
  • Mitigation Strategies:
    • Implement TLS/SSL encryption for all communication channels involving Twemproxy where feasible and supported.
    • Use network segmentation to limit the attack surface and potential interception points.
    • Consider VPNs or other secure tunnels if direct TLS/SSL is not fully supported in all communication paths.