Nosql Injection in Buffalo with Cockroachdb

Buffalo is a web framework for Go that encourages rapid development and a clean project structure. When building APIs with Buffalo, developers often integrate with databases such as CockroachDB, a distributed SQL database that also supports document-like operations via its JSONB type. Nosql Injection in this context arises when user-controlled input is used to construct query parameters, JSONB key lookups, or filter conditions without proper validation or escaping, allowing an attacker to manipulate query logic.

In Buffalo, requests are typically handled by actions that bind parameters from the URL, query string, or JSON body. If these inputs are directly interpolated into a database query—especially when building CockroachDB JSONB filters or constructing dynamic SQL via gorm—the application can become vulnerable. For example, an attacker may supply a payload like { "$ne": null } as a query parameter, which a naive filter may interpret as a JSONB condition, unintentionally returning additional documents or bypassing intended access controls.

The combination of Buffalo’s convention-based routing and CockroachDB’s JSONB capabilities exposes a larger attack surface. Queries that use raw map inputs to build WHERE clauses on JSONB columns can be manipulated to bypass authentication checks or extract data across tenant boundaries. This is especially risky when the API exposes unauthenticated endpoints or when role-based checks are implemented at the application layer rather than enforced at the database level.

Because Buffalo does not enforce strict schema validation on incoming parameters by default, developers must explicitly sanitize and constrain inputs before they reach the database layer. Without such controls, an API endpoint that appears to filter by a known set of fields can be tricked into evaluating arbitrary expressions, leading to data leakage or unauthorized modification of records.

middleBrick scans APIs for these classes of issue under its BOLA/IDOR and Input Validation checks, highlighting how unauthenticated or improperly constrained endpoints can be abused. Its LLM/AI Security checks further probe whether endpoints inadvertently expose system prompts or sensitive logic that could aid an attacker in crafting injection payloads.

To prevent Nosql Injection when using Buffalo with CockroachDB, ensure all user input is validated, parameterized, and never directly embedded into query structures. Prefer typed structs and ORM-based query building over raw map manipulation for JSONB fields.

1. Use Strong Typing and Explicit Field Selection

Define a struct that represents the expected shape of your data and bind only known fields. This prevents unexpected keys from being interpreted as query directives.

type FilterParams struct {
    Status string `json:"status"`
    Owner  string `json:"owner"`
}

func (rc ResourceController) Show(c buffalo.Context) error {
    var fp FilterParams
    if err := c.Bind(&fp); err != nil {
        return c.Render(400, r.JSON(Error{Message: "invalid parameters"}))
    }
    query := db.Model(&Record{})
    if fp.Status != "" {
        query = query.Where("status = ?", fp.Status)
    }
    if fp.Owner != "" {
        query = query.Where("owner = ?", fp.Owner)
    }
    var records []Record
    if err := query.Find(&records); err != nil {
        return c.Render(500, r.JSON(Error{Message: "server error"}))
    }
    return c.Render(200, r.JSON(records))
}

2. Avoid Dynamic JSONB Key Construction

When filtering on JSONB columns, do not directly pass user input as keys. Instead, map known keys to predefined conditions.

func (rc ResourceController) FilterByJSON(c buffalo.Context) error {
    var input map[string]interface{}
    if err := c.Bind(&input); err != nil {
        return c.Render(400, r.JSON(Error{Message: "invalid json"}))
    }

    // Only allow known safe keys
    allowedKeys := map[string]bool{
        "region": true,
        "active": true,
    }
    for key := range input {
        if !allowedKeys[key] {
            return c.Render(400, r.JSON(Error{Message: "unsupported filter key"}))
        }
    }

    // Build WHERE clauses safely
    clause := ""
    args := []interface{}{}
    idx := 1
    for key, val := range input {
        if clause != "" {
            clause += " AND "
        }
        clause += "jsonb_column @> ?"
        // Construct a JSONB value safely
        argBytes, _ := json.Marshal(map[string]interface{}{key: val})
        args = append(args, argBytes)
        idx++
    }

    var results []Record
    if err := db.Raw("SELECT * FROM records WHERE " + clause, args...).Scan(&results).Error; err != nil {
        return c.Render(500, r.JSON(Error{Message: "server error"}))
    }
    return c.Render(200, r.JSON(results))
}

3. Enforce Contextual Access Controls

Even when queries are parameterized, ensure that authorization checks are applied per request, using tenant or user identifiers that cannot be overridden by input.

func (rc ResourceController) SecureList(c buffalo.Context) error {
    userID, ok := c.Value("user_id").(string)
    if !ok {
        return c.Render(401, r.JSON(Error{Message: "unauthorized"}))
    }
    var records []Record
    // Always include tenant/user constraint in the query
    db.Where("user_id = ?", userID).Find(&records)
    return c.Render(200, r.JSON(records))
}

These practices reduce the risk of injection by ensuring that CockroachDB queries remain structured and that JSONB operations are constrained to known, safe patterns. The framework’s conventions should be leveraged to enforce strict parameter handling rather than relying on runtime interpretation of user-supplied structures.

middleBrick’s CLI tool can be used to validate your endpoints with a command such as middlebrick scan <url>, while the GitHub Action helps enforce security gates in CI/CD. For deeper analysis across multiple services, the Pro plan supports continuous monitoring and compliance mapping to frameworks such as OWASP API Top 10.