Ldap Injection in Buffalo

LDAP injection in Buffalo applications typically occurs when user-supplied input is concatenated directly into LDAP queries without proper sanitization. This vulnerability allows attackers to manipulate LDAP filters and potentially access unauthorized data or execute unauthorized operations against directory services.

In Buffalo applications, LDAP injection commonly appears in authentication middleware, user search functionality, and authorization systems that rely on directory services. The most vulnerable patterns involve using fmt.Sprintf or string concatenation to build LDAP queries from HTTP request parameters.

// Vulnerable Buffalo pattern
func ldapAuth(c buffalo.Context) error {
    username := c.Param("username")
    password := c.Param("password")
    
    // DANGEROUS: Direct string concatenation
    filter := fmt.Sprintf("(uid=%s)", username)
    
    // LDAP query using unfiltered input
    searchRequest := ldap.NewSearchRequest(
        "dc=example,dc=com",
        ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false,
        filter,
        []string{"uid", "cn", "mail"},
        nil,
    )
    
    // Execute query...
}

This pattern is particularly dangerous because LDAP filter syntax allows multiple logical operators. An attacker could supply a username like admin)(objectClass=* to bypass authentication or extract sensitive information.

Buffalo's middleware chain and parameter handling make LDAP injection especially relevant when integrating with Active Directory, OpenLDAP, or other directory services for user authentication. The framework's convention-over-configuration approach means developers often write custom LDAP integration code without realizing the security implications.

Common attack scenarios in Buffalo apps include:

• Authentication bypass by manipulating filter logic
• Information disclosure through directory traversal
• Denial of service by crafting expensive LDAP queries
• Privilege escalation by modifying group membership queries

Detecting LDAP injection in Buffalo applications requires both static code analysis and dynamic runtime testing. middleBrick's API security scanner includes specialized LDAP injection detection that works specifically with Buffalo applications.

For static detection, middleBrick scans your Buffalo codebase for dangerous patterns:

# Install middleBrick CLI
npm install -g middlebrick

# Scan a Buffalo API endpoint
middlebrick scan https://your-buffalo-app.com/api/v1/users

The scanner identifies LDAP injection risks by examining:

• Direct string formatting with user input in LDAP contexts
• Missing input validation before LDAP operations
• Unsafe parameter binding in LDAP queries
• Dynamic filter construction without escaping

middleBrick's dynamic analysis tests LDAP endpoints by sending specially crafted payloads that attempt to manipulate LDAP filter logic. The scanner checks for indicators like unexpected query results, error messages revealing directory structure, or authentication bypasses.

Buffalo-specific detection focuses on common integration patterns:

// Patterns middleBrick detects as risky
filter := fmt.Sprintf("(uid=%s)", c.Param("user")) // Direct interpolation
filter := "(uid=" + c.Param("user") + ")" // String concatenation
filter := fmt.Sprintf("(or=%s)", "(objectClass=*)") // Logical injection

The scanner also verifies proper use of LDAP escaping functions and checks whether your Buffalo application properly handles LDAP error responses to prevent information leakage.

For comprehensive coverage, middleBrick provides a Buffalo-specific security report that includes:

• LDAP injection risk score (0-100)
• Specific vulnerable code locations
• Recommended remediation steps
• Compliance mapping to OWASP API Top 10

Remediating LDAP injection in Buffalo applications requires a defense-in-depth approach using the framework's built-in features and Go's LDAP libraries. The primary defense is using parameterized LDAP queries instead of string concatenation.

Buffalo provides several patterns for secure LDAP integration:

import (
    "github.com/go-ldap/ldap/v3"
    "github.com/gobuffalo/buffalo"
)

// Secure pattern using parameterized queries
func secureLdapAuth(c buffalo.Context) error {
    username := c.Param("username")
    
    // Use LDAP escape functions
    escapedUsername := ldap.EscapeFilter(username)
    
    // Parameterized filter using proper escaping
    filter := fmt.Sprintf("(uid=%s)", escapedUsername)
    
    searchRequest := ldap.NewSearchRequest(
        "dc=example,dc=com",
        ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false,
        filter,
        []string{"uid", "cn", "mail"},
        nil,
    )
    
    return executeSearch(searchRequest)
}

// Even better: use search constraints
func secureSearch(c buffalo.Context) error {
    username := c.Param("username")
    
    // Set search size limit to prevent DoS
    searchRequest := ldap.NewSearchRequest(
        "dc=example,dc=com",
        ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 10, false, // 10 result limit
        "(uid="+ldap.EscapeFilter(username)+")",
        []string{"uid", "cn"},
        nil,
    )
    
    return executeSearch(searchRequest)
}

// Buffalo middleware for LDAP security
func LdapSecurityMiddleware(next buffalo.Handler) buffalo.Handler {
    return func(c buffalo.Context) error {
        // Validate input before LDAP operations
        username := c.Param("username")
        if !isValidLdapInput(username) {
            return c.Error(400, errors.New("invalid input"))
        }
        
        return next(c)
    }
}

func isValidLdapInput(input string) bool {
    // Basic validation: allow only expected characters
    if len(input) > 255 {
        return false
    }
    
    // Disallow special LDAP characters or use strict whitelist
    for _, char := range input {
        if !unicode.IsLetter(char) && !unicode.IsDigit(char) && char != '_' && char != '-' {
            return false
        }
    }
    
    return true
}

// Register middleware in buffalo.App
app := buffalo.New(buffalo.Options{
    // ... other options
})

// Apply LDAP security middleware to specific routes
app.Use(LdapSecurityMiddleware)
app.POST("/api/v1/ldap/auth", ldapAuthHandler)

For Buffalo applications using Active Directory, consider using the github.com/go-ldap/ldap/v3 library's built-in authentication methods which handle escaping automatically:

// Secure AD authentication
func adAuth(c buffalo.Context) error {
    username := c.Param("username")
    password := c.Param("password")
    
    // Use simple bind with proper escaping
    conn, err := ldap.DialURL("ldap://ad.example.com")
    if err != nil {
        return err
    }
    defer conn.Close()
    
    // The library handles escaping for simple bind
    userDn := fmt.Sprintf("uid=%s,ou=users,dc=example,dc=com", ldap.EscapeFilter(username))
    
    err = conn.Bind(userDn, password)
    if err != nil {
        return c.Error(401, err)
    }
    
    return c.Render(200, r.JSON(map[string]string{"status": "authenticated"}))
}

Buffalo's validation package can also help sanitize input before it reaches LDAP operations:

import "github.com/go-playground/validator/v10"

type ldapParams struct {
    Username string `json:"username" validate:"ldapinput"`
    Password string `json:"password" validate:"min=8"`
}

// Custom validator for LDAP input
func ldapInputValidator(fl validator.FieldLevel) bool {
    value := fl.Field().String()
    // Implement your LDAP-safe character validation
    return isValidLdapInput(value)
}

// Register custom validation
func init() {
    validate := validator.New()
    validate.RegisterValidation("ldapinput", ldapInputValidator)
}