/// <reference types="express" />
import { Request } from '@loopback/rest';
import { XssConfig } from '../types';
import { SecurityLogger } from '../utils/security-logger';
/**
 * XSS detector that scans for cross-site scripting attack patterns
 */
export declare class XssDetector {
    private config?;
    private logger?;
    private readonly defaultPatterns;
    private patterns;
    private allowedTags;
    private allowedAttributes;
    private skipFields;
    constructor(config?: XssConfig | undefined, logger?: SecurityLogger | undefined, skipFields?: string[]);
    /**
     * Detect XSS attacks in the request
     */
    detectXssAttacks(req: Request): Promise<void>;
    /**
     * Check if a field should be skipped from XSS detection
     */
    private shouldSkipField;
    /**
     * Scan object recursively for XSS patterns
     */
    private scanObject;
    /**
     * Scan headers for XSS attempts
     */
    private scanHeaders;
    /**
     * Scan header values with more restrictive patterns to avoid false positives
     * while still catching obvious XSS attempts
     */
    private scanHeaderValueCarefully;
    /**
     * Helper method to log and throw XSS detection
     */
    private logAndThrowXss;
    /**
     * Scan individual string value for XSS patterns
     */
    private scanStringValue;
    /**
     * Decode various encodings to catch evasion attempts
     */
    private decodeValue;
    /**
     * Check if content might be allowed based on configuration
     */
    private isAllowedContent;
    /**
     * Determine if pattern represents high-risk XSS attempt
     */
    private isHighRiskPattern;
    /**
     * Determine if pattern should be blocked even in non-strict mode
     */
    private shouldBlockPattern;
    /**
     * Sanitize request data in place
     */
    private sanitizeRequestData;
    /**
     * Apply sanitization to nested object structure
     */
    private applySanitization;
    /**
     * Sanitize value for logging (remove sensitive content)
     */
    private sanitizeLogValue;
    /**
     * Add custom pattern to detection
     */
    addCustomPattern(pattern: RegExp): void;
    /**
     * Add allowed tag
     */
    addAllowedTag(tag: string): void;
    /**
     * Add allowed attribute
     */
    addAllowedAttribute(attribute: string): void;
    /**
     * Get detection statistics
     */
    getStats(): Record<string, unknown>;
    /**
     * Update configuration
     */
    updateConfig(config: Partial<XssConfig>): void;
}