Cryptographic Failures in Chi with Basic Auth

The combination of cryptographic failures and Basic Authentication in Chi creates a high-risk scenario because credentials are transmitted with minimal protection. Basic Authentication encodes credentials using Base64, which is not encryption, and can be trivially decoded. If an API endpoint in Chi relies solely on Basic Auth without enforcing TLS, credentials are exposed in cleartext across the network. middleBrick detects this as a cryptographic failure by identifying missing or weak transport-layer protections during unauthenticated scans, flagging the absence of required ciphers and secure protocol versions.

Even when TLS is present, cryptographic failures can arise from improper configuration, such as using deprecated algorithms (e.g., RC4, MD5) or failing to enforce strong cipher suites. middleBrick’s encryption checks identify weak configurations and missing HTTP Strict Transport Security (HSTS) headers, which can lead to protocol downgrade attacks. For example, an API in Chi that accepts both HTTP and HTTPS without redirecting or enforcing HTTPS may allow an attacker to intercept credentials via a man-in-the-middle attack. The scanner correlates these weaknesses with the use of Basic Auth, highlighting endpoints where credentials could be captured even when transmitted over TLS if the cryptographic implementation is flawed.

Another dimension of cryptographic failure involves the storage and handling of credentials on the server side. Basic Auth credentials are often stored as encoded strings rather than salted, hashed values. If the backend in Chi stores these credentials insecurely, a data exposure vulnerability may exist. middleBrick’s data exposure checks examine how credentials are handled and stored, identifying cases where Base64-encoded strings are used in place of proper password hashing. This is particularly relevant when APIs expose endpoints that return authorization headers or logs containing raw credentials, increasing the risk of credential leakage through logs or error messages.

SSRF and input validation checks performed by middleBrick further reveal how cryptographic failures can be exploited in Chi. An attacker may manipulate server-side requests to internal services that rely on Basic Auth, bypassing network restrictions. If the API does not validate or sanitize inputs related to authentication headers, it may inadvertently expose credentials to internal endpoints that lack proper access controls. The scanner tests for these scenarios by sending malicious payloads designed to trigger unauthorized access or credential exposure, ensuring that cryptographic protections are verified not only in transit but also in how the application processes authentication data.

Finally, the LLM/AI Security module of middleBrick evaluates whether any AI-related endpoints in Chi that use Basic Auth are susceptible to prompt injection or output leakage. Although Basic Auth is not directly tied to LLM systems, endpoints that handle authentication and AI responses may inadvertently expose credentials through model outputs or logs. By analyzing responses for sensitive data such as API keys or credentials, the scanner ensures that cryptographic failures do not intersect with AI functionality, providing a comprehensive view of security risk specific to Chi environments using Basic Auth.

Remediation for cryptographic failures with Basic Auth in Chi centers on replacing Basic Auth with more secure authentication mechanisms and enforcing strict transport security. Where possible, migrate to token-based authentication such as OAuth 2.0 or API keys with short lifetimes. If Basic Auth must be used, ensure it is transmitted exclusively over HTTPS with strong cipher suites and HSTS enabled. The following examples demonstrate secure implementations in Chi using environment variables and middleware to enforce these practices.

Enforcing HTTPS and Secure Headers

Ensure all API endpoints in Chi redirect HTTP to HTTPS and include security headers. Below is an example using a Chi web server in Common Lisp:

(ql:quickload '(:cl-whoops :hunchentoot))

(defun enforce-https (request reply)
  (when (string= (header-in "X-Forwarded-Proto") "http")
    (setf (reply-header-out "Location") (format nil "https://~a" (raw-post request)))
    (setf (reply-code) 301)
    (finish reply)))

(defun add-security-headers (request reply)
  (setf (reply-header-out "Strict-Transport-Security") "max-age=31536000; includeSubDomains"
        (reply-header-out "Content-Security-Policy") "default-src 'none'; connect-src 'self'; script-src 'none'; style-src 'none'"))

(define-easy-handler (home-page :uri "/") ()
  "Secure endpoint example.")

(push (create-instance 'easy-acceptor :port 443 :ssl-certificate-file "server.crt" :ssl-key-file "server.key") *acceptors*)
(setf *after-request-hooks* (list #'enforce-https #'add-security-headers))

Using Environment Variables for Credentials

Avoid hardcoding credentials in Chi applications. Instead, retrieve Basic Auth credentials from environment variables and validate them securely:

(defun get-basic-auth-credentials (request)
  (let ((auth-header (header-in "Authorization")))
    (when (and auth-header (starts-with auth-header "Basic "))
      (let* ((encoded-credentials (subseq auth-header 6))
             (decoded (base64:decode-string encoded-credentials :element-type '(unsigned-byte 8)))
             (credentials (babel:octets-to-string decoded :encoding :utf-8)))
        (multiple-value-bind (username password)
            (parse-credentials-string credentials)
          (validate-credentials username password)))))

(defun validate-credentials (username password)
  (and (string= username (uiop:getenv "API_USER"))
       (string= password (uiop:getenv "API_PASS"))))

;; Example route using the above
(define-easy-handler (auth-protected :uri "/secure") ()
  (if (get-basic-auth-credentials request)
      (format t "Access granted")
      (progn
        (setf (reply-code) 401)
        (setf (reply-header-out "WWW-Authenticate") "Basic realm=\"Chi API\"")
        (format t "Unauthorized"))))

Middleware for Credential Validation

Implement middleware in Chi to validate credentials on each request and avoid storing sensitive data in logs:

(defun auth-middleware (app)
  (lambda (env)
    (let ((request (create-request env)))
      (if (get-basic-auth-credentials request)
          (funcall app env)
          (response :status 401
                    :headers '((:www-authenticate . "Basic realm=\"Chi API\"")
                               (:content-type . "text/plain"))
                    :body "Authentication required")))))

;; Apply middleware to your application
(setq app (auth-middleware #'home-page))

These examples illustrate how to secure Basic Auth usage in Chi by enforcing HTTPS, avoiding hardcoded credentials, and implementing validation middleware. For stronger security, consider migrating to token-based authentication, which is natively supported by middleBrick’s authentication checks and reduces the risk associated with Basic Auth’s inherent limitations.