Partner API boundary security

Partner APIs expand your attack surface by exposing endpoints to external integrations that may have weaker security postures. Common issues include missing access controls on partner-specific endpoints, inconsistent authentication, and data leakage through verbose error messages. Because partners often operate in different trust zones, you need visibility into how requests are authenticated, rate-limited, and validated before sensitive data crosses boundaries.

Without continuous assessment of partner-facing endpoints, misconfigured authentication and authorization mechanisms remain undetected. Teams may rely on network perimeter controls alone, which do not protect against over-permissive scopes, IDOR on partner-managed identifiers, or unsafe data exposure in responses. Over time, this increases the risk of lateral movement, data exfiltration, and compliance gaps when handling regulated information.

Start with reconnaissance to map public endpoints and supported methods, then authenticate with supported mechanisms such as Bearer tokens, API keys, Basic auth, or cookies. Run a boundary scan to validate authentication resilience, test IDOR via sequential and adjacent ID probing, verify security headers and HTTPS configurations, and inspect responses for sensitive data exposure. Prioritize findings by risk score and review remediation guidance for each category aligned to OWASP API Top 10.

Example CLI usage:

middlebrick scan https://partners.example.com/api

middleBrick performs black-box scanning to detect issues across authentication, BOLA/IDOR, BFLA/privilege escalation, property authorization, input validation, rate limiting, data exposure, encryption, SSRF, inventory management, unsafe consumption, and LLM/AI security probes. The scanner parses OpenAPI 3.0, 3.1, and Swagger 2.0 definitions, cross-references spec security schemes with runtime behavior, and supports authenticated scans with header allowlists. Continuous monitoring options can track score drift and surface new findings across scheduled intervals.

findings map to OWASP API Top 10 (2023), and help you prepare for SOC 2 Type II and PCI-DSS 4.0 controls. The tool surfaces findings relevant to audit evidence for security reviews but does not certify compliance. It does not perform active SQL injection or command injection testing, detect business logic flaws that require domain context, or replace a human pentester for high-stakes audits. Destructive payloads are never sent, and private IPs, localhost, and cloud metadata endpoints are blocked at multiple layers.