Phishing Api Keys in Buffalo with Jwt Tokens

In a Buffalo application, storing API keys as bearer tokens in JWTs can expose both the keys and the tokens to phishing when authentication or token handling is not hardened. A JWT typically carries claims and is signed with a secret or private key; if the signing secret or a hardcoded API key is leaked, attackers can forge tokens or exfiltrate credentials used by the service.

Phishing in this context often targets developers or operators who inadvertently embed secrets in client-side code, logs, or error messages. For example, if a Buffalo handler decodes a JWT without strict validation and uses a claim to derive an API key, a phishing site can lure users or developers into triggering endpoints that leak the key or token. The combination is risky because JWTs are often transported in URLs, headers, or logs, and Buffalo routes may expose these vectors if input validation, authentication middleware, and secure cookie settings are not properly configured.

Attack patterns include social engineering to obtain developer API keys stored in environment configurations, or tricking users into authenticating through a spoofed Buffalo app that captures JWTs. If a JWT is issued without short expiration or without proper audience/issuer checks, a phished token can be reused. Additionally, if the Buffalo app logs full requests including authorization headers, those logs can become targets for phishing collectors. The OWASP API Security Top 10 highlights broken authentication and excessive data exposure as common concerns, and improper JWT usage can map to these issues, especially when API keys are embedded in tokens without adequate protection.

To detect such risks, middleBrick scans unauthenticated attack surfaces and performs checks including Input Validation, Authentication, and Data Exposure, which help identify insecure JWT handling and exposed API keys. The LLM/AI Security checks specifically look for system prompt leakage and output patterns that could reveal secrets, while the inventory and unsafe consumption checks assess how API keys and tokens are managed across endpoints.

Remediation focuses on secure JWT creation, validation, and storage within Buffalo handlers. Always use strong algorithms, validate claims, and avoid logging sensitive data. Below are concrete code examples for Buffalo (Go) that demonstrate secure practices.

1. Generate and verify JWTs securely

Use a well-maintained library such as github.com/golang-jwt/jwt/v5. Set short expirations, enforce issuer and audience, and use strong signing methods.

import (
    "time"
    "github.com/golang-jwt/jwt/v5"
)

// Secret key should be stored securely, e.g., from environment variables.
var jwtSecret = []byte("your-very-secure-secret-key-min-32-bytes-long-for-hs256")

func GenerateToken(userID string) (string, error) {
    claims := jwt.RegisteredClaims{
        Subject:   userID,
        Issuer:    "buffalo-app",
        Audience:  jwt.ClaimStrings{"buffalo-api"},
        ExpiresAt: jwt.NewNumericDate(time.Now().Add(15 * time.Minute)),
        NotBefore: jwt.NewNumericDate(time.Now()),
        IssuedAt:  jwt.NewNumericDate(time.Now()),
    }
    token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
    return token.SignedString(jwtSecret)
}

func ValidateToken(rawToken string) (*jwt.Token, error) {
    return jwt.Parse(rawToken, func(token *jwt.Token) (interface{}, error) {
        if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
            return nil = fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
        }
        return jwtSecret, nil
    }, jwt.WithValidators(
        jwt.WithIssuer("buffalo-app"),
        jwt.WithAudience("buffalo-api"),
    ))
}

2. Use secure cookies for session tokens

If storing JWTs in cookies, set HttpOnly, Secure, SameSite, and appropriate path/domain flags to mitigate XSS and CSRF, reducing phishing impact.

import (
    "github.com/gorilla/sessions"
)

var store = sessions.NewCookieStore([]byte("cookie-store-secret-key-at-least-32-bytes"))

func SetSessionToken(w buffalo.Response, token string) error {
    session, _ := store.Get(w, "session_name")
    session.Values["token"] = token
    session.Options = &sessions.Options{
        HttpOnly:   true,
        Secure:     true,   // only over HTTPS
        SameSite:   http.SameSiteStrictMode,
        MaxAge:     900,    // 15 minutes
        Path:       "/",
    }
    return session.Save(w, w.Request())
}

3. Avoid exposing API keys in client-side code or logs

Ensure API keys used for downstream services are not embedded in JavaScript or logged in plaintext. Use server-side calls and scrub logs.

// Example: call external service using API key from environment, not exposed to client.
func CallProtectedService() error {
    apiKey := os.Getenv("EXTERNAL_API_KEY")
    req, _ := http.NewRequest("GET", "https://api.example.com/data", nil)
    req.Header.Set("Authorization", "Bearer "+apiKey)
    // Do not log apiKey; use structured logging with redaction if needed.
    resp, err := http.DefaultClient.Do(req)
    if err != nil {
        return err
    }
    defer resp.Body.Close()
    if resp.StatusCode != http.StatusOK {
        return fmt.Errorf("unexpected status: %d", resp.StatusCode)
    }
    return nil
}

4. Validate inputs and set rate limits to reduce phishing surface

Buffalo middleware can enforce strict host policies and rate limiting to reduce abuse vectors that phishing attempts exploit.

import (
    "github.com/gobuffalo/buffalo"
    "github.com/gobuffalo/buffalo/middleware"
)

func App() *buffalo.App {
    app := buffalo.New(buffalo.Options{})
    // Enforce strict Host header validation to prevent host header attacks.
    app.Use(middleware.ParameterSanitizer)
    app.Use(middleware.RequestID)
    app.Use(middleware.Secure)
    // Rate limiting helps mitigate brute-force and phishing-driven request floods.
    app.Use(middleware.RateLimit(100)) // example: 100 requests per minute
    return app
}