Ldap Injection in Buffalo with Cockroachdb

LDAP Injection occurs when untrusted input is concatenated into LDAP query strings, allowing an attacker to alter the query’s logic. In a Buffalo application using Cockroachdb as the primary datastore, LDAP is typically used for authentication or group membership checks. If the application builds LDAP filter strings by directly interpolating user-supplied values (e.g., uid or email), an attacker can inject crafted filter syntax to bypass authentication or extract directory data.

Consider a Buffalo handler that authenticates a user against an LDAP server using a username from a form parameter. If the code builds the filter as (&(objectClass=person)(uid=${username})), an attacker providing admin)(&objectClass=*) as the username can change the effective filter to (&(objectClass=person)(uid=admin)(&objectClass=*)), potentially returning all user entries or bypassing the uid check entirely. The presence of Cockroachdb does not mitigate this because the vulnerability exists in how the application constructs the LDAP filter before any database or directory interaction. Cockroachdb may be queried afterward for user metadata, but the LDAP injection path is independent of the SQL layer.

Buffalo’s middleware pipeline can inadvertently expose this risk if authentication logic is placed in before actions that rely on unchecked request parameters. For example, an action that reads params.Get("username") and uses it to form an LDAP filter without sanitization or escaping enables injection. Attackers may also probe for unauthenticated LDAP endpoints if the service is exposed without network restrictions. While this specific chain involves directory services rather than SQL, the impact can be severe: unauthorized access, information disclosure, or privilege escalation within the identity provider. The scanner’s LLM/AI Security checks and authentication tests are designed to surface such unauthenticated attack surfaces and injection-prone entry points.

Remediation centers on strict input validation and using parameterized or library-supported constructs for LDAP queries, never string concatenation. In Buffalo, you should treat LDAP input as untrusted and apply allow-listing for acceptable characters, rejecting unexpected patterns early. The application should also enforce proper error handling to avoid leaking stack traces or directory structure details that could aid an attacker. Regular scans with a tool like middleBrick can identify these injection-prone patterns in unauthenticated scans and map findings to relevant frameworks such as OWASP API Top 10.

While Cockroachdb is not the vector for LDAP Injection, securing the Buffalo application requires disciplined handling of all external inputs and clear separation between directory authentication and database operations. Use parameterized queries or an ORM to interact with Cockroachdb, and ensure LDAP filters are built using dedicated libraries that escape special characters.

Example of a vulnerable Buffalo handler that concatenates user input into an LDAP filter and also builds a Cockroachdb query by string interpolation:

// DO NOT DO THIS
func (r UserResource) Show(c buffalo.Context) error {
    username := c.Param("username")
    // Unsafe LDAP filter construction
    ldapFilter := fmt.Sprintf("(&(objectClass=person)(uid=%s))", username)
    // Unsafe Cockroachdb query construction
    query := fmt.Sprintf("SELECT id, email FROM users WHERE username = '%s'", username)
    var user User
    if err := r.DB.QueryOne(&user, query); err != nil {
        return c.Render(500, r.JSON(Map{"error": err.Error()}))
    }
    // LDAP bind using ldapFilter (omitted for brevity)
    return c.Render(200, r.JSON(user))
}

The LDAP filter and SQL query are both vulnerable to injection. An attacker can manipulate username to affect both the directory lookup and the SQL execution.

Secure version using parameterized Cockroachdb queries and a safe LDAP filter builder:

// SECURE: parameterized SQL and escaped LDAP filter
import (
    "github.com/gobuffalo/buffalo"
    "github.com/gobuffalo/pop/v6"
    "github.com/go-ldap/ldap/v3"
)

func (r UserResource) Show(c buffalo.Context) error {
    username := c.Param("username")
    // Validate input: allow only alphanumeric and limited special chars
    if !regexp.MustCompile(`^[a-zA-Z0-9._-]+$`).MatchString(username) {
        return c.Render(400, r.JSON(Map{"error": "invalid username"}))
    }
    // Safe Cockroachdb query with pop (parameterized)
    var user User
    if err := r.DB.Where("username = ?", username).First(&user); err != nil {
        return c.Render(404, r.JSON(Map{"error": "not found"}))
    }
    // Build LDAP filter using proper escaping from the ldap package
    filter := ldap.NewFilter().
        Equals("objectClass", "person").
        And(ldap.NewFilter().Equals("uid", username)).
        Build()
    // Use ldap.Bind with the constructed filter and a separate password check
    // ldapConn.Bind(dn, password) would follow here
    return c.Render(200, r.JSON(user))
}

In this secure version, Cockroachdb interaction uses parameterized conditions via pop, ensuring SQL arguments are never interpreted as code. The LDAP filter is built with github.com/go-ldap/ldap/v3, which properly escapes special characters in the uid value, neutralizing injection attempts. Input validation further reduces the attack surface by rejecting unexpected characters before any directory or database call.

For continuous assurance, integrate middleBrick into your workflow: use the CLI to scan from terminal with middlebrick scan <url>, add API security checks to your CI/CD pipeline with the GitHub Action, or run scans directly from your IDE via the MCP Server. These scans can detect unauthenticated endpoints and injection-prone patterns, complementing secure coding practices.