解決AppScan掃描的問題SQL注入/XSS攻擊

    客戶使用IBM的安全漏洞掃描工具AppScan掃出來一堆問題，如SQL盲注、綁定 MongoDB NoSQL 注入、跨站點腳本編制、已解密的登錄請求、跨站點請求僞造、鏈接注入（便於跨站請求僞造）、通過框架釣魚等等。
    要解決此類問題，增加過濾器是比較簡單的方法：把用戶輸入的非法字符進行轉移。

1. XssAndSqlFilter.java

package com.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

public class XssAndSqlFilter implements Filter
{

	@Override
	public void destroy()
	{
		System.out.println("[XssAndSqlFilter] destroy success!");
	}

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException,
			ServletException
	{
		XssAndSqlHttpServletRequestWrapper xssRequest = new XssAndSqlHttpServletRequestWrapper(
				(HttpServletRequest) request);
		chain.doFilter(xssRequest, response);
	}

	@Override
	public void init(FilterConfig arg0) throws ServletException
	{
		System.out.println("[XssAndSqlFilter] init success!");
	}

}

2. XssAndSqlHttpServletRequestWrapper.java

package com.filter;

import java.util.regex.Pattern;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

public class XssAndSqlHttpServletRequestWrapper extends HttpServletRequestWrapper
{
	HttpServletRequest orgRequest = null;

	public XssAndSqlHttpServletRequestWrapper(HttpServletRequest request)
	{
		super(request);
		orgRequest = request;
	}

	/**
	 * 覆蓋getParameter方法，將參數名和參數值都做xss & sql過濾。<br/>
	 * 如果需要獲得原始的值，則通過super.getParameterValues(name)來獲取<br/>
	 * getParameterNames,getParameterValues和getParameterMap也可能需要覆蓋
	 */
	@Override
	public String getParameter(String name)
	{
		String value = super.getParameter(xssEncode(name));
		if (value != null)
		{
			value = xssEncode(value);
		}
		return value;
	}

	/**
	 * 覆蓋getHeader方法，將參數名和參數值都做xss & sql過濾。<br/>
	 * 如果需要獲得原始的值，則通過super.getHeaders(name)來獲取<br/>
	 * getHeaderNames 也可能需要覆蓋
	 */
	@Override
	public String getHeader(String name)
	{
		String value = super.getHeader(xssEncode(name));
		if (value != null)
		{
			value = xssEncode(value);
		}
		return value;
	}

	/**
	 * 將容易引起xss & sql漏洞的半角字符直接替換成全角字符
	 * 
	 * @param s
	 * @return
	 */
	private static String xssEncode(String s)
	{
		if (s == null || s.isEmpty())
		{
			return s;
		}
		else
		{
			s = stripXSSAndSql(s);
		}
		StringBuilder sb = new StringBuilder(s.length() + 16);
		for (int i = 0; i < s.length(); i++)
		{
			char c = s.charAt(i);
			switch (c)
			{
			case '>':
				sb.append("＞");// 轉義大於號
				break;
			case '<':
				sb.append("＜");// 轉義小於號
				break;
			case '\'':
				sb.append("＇");// 轉義單引號
				break;
			case '\"':
				sb.append("＂");// 轉義雙引號
				break;
			case '&':
				sb.append("＆");// 轉義&
				break;
			case '#':
				sb.append("＃");// 轉義#
				break;
			default:
				sb.append(c);
				break;
			}
		}
		return sb.toString();
	}

	/**
	 * 獲取最原始的request
	 * 
	 * @return
	 */
	public HttpServletRequest getOrgRequest()
	{
		return orgRequest;
	}

	/**
	 * 獲取最原始的request的靜態方法
	 * 
	 * @return
	 */
	public static HttpServletRequest getOrgRequest(HttpServletRequest req)
	{
		if (req instanceof XssAndSqlHttpServletRequestWrapper)
		{
			return ((XssAndSqlHttpServletRequestWrapper) req).getOrgRequest();
		}
		return req;
	}

	/**
	 * 
	 * 防止xss跨腳本攻擊（替換，根據實際情況調整）
	 */
	public static String stripXSSAndSql(String value)
	{
		if (value != null)
		{
			Pattern scriptPattern = Pattern.compile(
					"<[\r\n| | ]*script[\r\n| | ]*>(.*?)</[\r\n| | ]*script[\r\n| | ]*>", Pattern.CASE_INSENSITIVE);
			value = scriptPattern.matcher(value).replaceAll("");
			scriptPattern = Pattern.compile("src[\r\n| | ]*=[\r\n| | ]*[\\\"|\\\'](.*?)[\\\"|\\\']",
					Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
			value = scriptPattern.matcher(value).replaceAll("");
			scriptPattern = Pattern.compile("</[\r\n| | ]*script[\r\n| | ]*>", Pattern.CASE_INSENSITIVE);
			value = scriptPattern.matcher(value).replaceAll("");
			scriptPattern = Pattern.compile("<[\r\n| | ]*script(.*?)>", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE
					| Pattern.DOTALL);
			value = scriptPattern.matcher(value).replaceAll("");
			scriptPattern = Pattern.compile("eval\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE
					| Pattern.DOTALL);
			value = scriptPattern.matcher(value).replaceAll("");
			scriptPattern = Pattern.compile("e-xpression\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE
					| Pattern.DOTALL);
			value = scriptPattern.matcher(value).replaceAll("");
			scriptPattern = Pattern.compile("javascript[\r\n| | ]*:[\r\n| | ]*", Pattern.CASE_INSENSITIVE);
			value = scriptPattern.matcher(value).replaceAll("");
			scriptPattern = Pattern.compile("vbscript[\r\n| | ]*:[\r\n| | ]*", Pattern.CASE_INSENSITIVE);
			value = scriptPattern.matcher(value).replaceAll("");
			scriptPattern = Pattern.compile("onload(.*?)=", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE
					| Pattern.DOTALL);
			value = scriptPattern.matcher(value).replaceAll("");
		}
		return value;
	}
}

3. web.xml

<!-- 解決xss & sql漏洞 -->
<filter>  
	<filter-name>xssAndSqlFilter</filter-name>  
	<filter-class>com.zxwl.common.filter.XssAndSqlFilter</filter-class>  
</filter>  
<filter-mapping>  
	<filter-name>xssAndSqlFilter</filter-name>  
	<url-pattern>/*</url-pattern>  
</filter-mapping>

參考鏈接：

• 防止SQL注入和XSS攻擊filter
• 防止常見XSS 過濾 SQL注入 JAVA過濾器filter