/// <reference types="express" />
import { Request } from '@loopback/rest';
import { SqlInjectionConfig } from '../types';
import { SecurityLogger } from '../utils/security-logger';
/**
 * SQL injection detector that scans for common SQL injection patterns
 */
export declare class SqlInjectionDetector {
    private config?;
    private logger?;
    private readonly defaultPatterns;
    private patterns;
    private whitelistedQueries;
    private skipFields;
    constructor(config?: SqlInjectionConfig | undefined, logger?: SecurityLogger | undefined, skipFields?: string[]);
    /**
     * Detect SQL injection attempts in the request
     */
    detectSqlInjection(req: Request): Promise<void>;
    /**
     * Check if a field should be skipped from SQL injection detection
     */
    private shouldSkipField;
    /**
     * Scan object recursively for SQL injection patterns
     */
    private scanObject;
    /**
     * Scan URL parameters with more lenient patterns to allow legitimate URL characters
     */
    private scanUrlParameter;
    /**
     * Scan headers for SQL injection attempts
     */
    private scanHeaders;
    /**
     * Scan header values with more restrictive patterns to avoid false positives
     * while still catching obvious SQL injection attempts
     */
    private scanHeaderValueCarefully;
    /**
     * Helper method to log and throw SQL injection detection
     */
    private logAndThrowSqlInjection;
    /**
     * Scan individual string value for SQL injection patterns
     */
    private scanStringValue;
    /**
     * Check if a query is whitelisted
     */
    private isWhitelisted;
    /**
     * Decode URL-encoded and other encoded values for better detection
     */
    private decodeValue;
    /**
     * Check if base64 string might contain SQL injection
     */
    private mightBeSqlInjectionBase64;
    /**
     * Check if string looks like base64
     */
    private isBase64;
    /**
     * Determine if pattern represents high-risk SQL injection attempt
     */
    private isHighRiskPattern;
    /**
     * Sanitize value for logging (remove sensitive content)
     */
    private sanitizeLogValue;
    /**
     * Add custom pattern to detection
     */
    addCustomPattern(pattern: RegExp): void;
    /**
     * Add query to whitelist
     */
    addWhitelistedQuery(query: string): void;
    /**
     * Remove query from whitelist
     */
    removeWhitelistedQuery(query: string): void;
    /**
     * Get detection statistics
     */
    getStats(): Record<string, unknown>;
    /**
     * Simple hash function for logging purposes
     */
    private hashString;
    /**
     * Update configuration
     */
    updateConfig(config: Partial<SqlInjectionConfig>): void;
}