XSS漏洞修补及预防--使用过滤器
什么是XSS攻击 ：
XSS是一种经常出现在web应用中的计算机安全漏洞，它允许恶意web用户将代码植入到提供给其它用户使用的页面中。比如这些代码包括HTML代码和客户端脚本。攻击者利用XSS漏洞旁路掉访问控制——例如同源策略(same origin policy)。这种类型的漏洞由于被黑客用来编写危害性更大的网络钓鱼(Phishing)攻击而变得广为人知。对于跨站脚本攻击，黑客界共识是：跨站脚本攻击是新型的“缓冲区溢出攻击“，而JavaScript是新型的“ShellCode”。
如下代码不涉及对原有开发人员的代码，进行修改。在最外层增加过滤器，进行对所有参数进行过滤，涉及框架SpringMVC
1.创建过滤器类，使其实现Filter。
package com.data.interceptor;
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;
/** * * @Title: XSSFilter.java * @Package: com.data.interceptor * @author you.xu * @date 2016年3月4日上午11:21:47 * @version 1.0 */
public class XSSFilter implements Filter {
public void init(FilterConfig filterConfig) throws ServletException {
}
public void doFilter(ServletRequest req, ServletResponse res,
FilterChain filterChain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) req;
request = new XSSServletRequest(request);
filterChain.doFilter(request, res);
}
public void destroy() {
}
}
2.创建XSSServletRequest.java类，将request请求进行过滤。
package com.data.interceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import com.data.utils.XssFilterUtil;
/** * * @Title: XSSServletRequest.java * @Package: com.data.interceptor * @author you.xu * @date 2016年3月4日上午11:25:02 * @version 1.0 */
public class XSSServletRequest extends HttpServletRequestWrapper {
public XSSServletRequest(HttpServletRequest request) {
super(request);
}
@Override
public String getParameter(String name) {
String string = super.getParameter(name);
// 返回值之前 先进行过滤
return XssFilterUtil.stripXss(string);
}
@Override
public String[] getParameterValues(String name) {
// 返回值之前 先进行过滤
String[] values = super
.getParameterValues(name);
if (values != null) {
for (int i = 0; i < values.length; i++) {
values[i] = XssFilterUtil.stripXss(values[i]);
}
}
return values;
}
}
3.创建过滤器工具类XssFilterUtil.java，
package com.data.utils;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.lang.StringUtils;
/** * * @Title: XssFilterUtil.java * @author you.xu * @date 2016年3月4日上午9:52:02 * @version 1.0 */
public class XssFilterUtil {
private static List<Pattern> patterns = null;
private static List<Object[]> getXssPatternList() {
List<Object[]> ret = new ArrayList<Object[]>();
ret.add(new Object[] { "<(no)?script[^>]*>.*?</(no)?script>",
Pattern.CASE_INSENSITIVE });
ret.add(new Object[] { "eval\\((.*?)\\)",
Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL });
ret.add(new Object[] { "expression\\((.*?)\\)",
Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL });
ret.add(new Object[] { "(javascript:|vbscript:|view-source:)*",
Pattern.CASE_INSENSITIVE });
ret.add(new Object[] { "<(\"[^\"]*\"|\'[^\']*\'|[^\'\">])*>",
Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL });
ret.add(new Object[] {
"(window\\.location|window\\.|\\.location|document\\.cookie|document\\.|alert\\(.*?\\)|window\\.open\\()*",
Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL });
ret.add(new Object[] {
"<+\\s*\\w*\\s*(oncontrolselect|oncopy|oncut|ondataavailable|ondatasetchanged|ondatasetcomplete|ondblclick|ondeactivate|ondrag|ondragend|ondragenter|ondragleave|ondragover|ondragstart|ondrop|onerror=|onerroupdate|onfilterchange|onfinish|onfocus|onfocusin|onfocusout|onhelp|onkeydown|onkeypress|onkeyup|onlayoutcomplete|onload|onlosecapture|onmousedown|onmouseenter|onmouseleave|onmousemove|onmousout|onmouseover|onmouseup|onmousewheel|onmove|onmoveend|onmovestart|onabort|onactivate|onafterprint|onafterupdate|onbefore|onbeforeactivate|onbeforecopy|onbeforecut|onbeforedeactivate|onbeforeeditocus|onbeforepaste|onbeforeprint|onbeforeunload|onbeforeupdate|onblur|onbounce|oncellchange|onchange|onclick|oncontextmenu|onpaste|onpropertychange|onreadystatechange|onreset|onresize|onresizend|onresizestart|onrowenter|onrowexit|onrowsdelete|onrowsinserted|onscroll|onselect|onselectionchange|onselectstart|onstart|onstop|onsubmit|onunload)+\\s*=+",
Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL });
return ret;
}
private static List<Pattern> getPatterns() {
if (patterns == null) {
List<Pattern> list = new ArrayList<Pattern>();
String regex = null;
Integer flag = null;
int arrLength = 0;
for (Object[] arr : getXssPatternList()) {
arrLength = arr.length;
for (int i = 0; i < arrLength; i++) {
regex = (String) arr[0];
flag = (Integer) arr[1];
list.add(Pattern.compile(regex, flag));
}
}
patterns = list;
}
return patterns;
}
public static String stripXss(String value) {
if (null == value) {
return value;
}
if (StringUtils.isNotBlank(value)) {
Matcher matcher = null;
for (Pattern pattern : getPatterns()) {
matcher = pattern.matcher(value);
// 匹配
if (matcher.find()) {
// 删除相关字符串
value = matcher.replaceAll("");
}
}
value = StringFilter.StringFilter(value);
}
// 预防SQL盲注
String[] pattern = { "%", "select", "insert", "delete", "from",
"count\\(", "drop table", "update", "truncate", "asc\\(",
"mid\\(", "char\\(", "xp_cmdshell", "exec", "master",
"netlocalgroup administrators", "net user", "or", "and" };
for (int i = 0; i < pattern.length; i++) {
value = value.replace(pattern[i].toString(), "");
}
return value;
}
public static void main(String[] args) {
String value = null;
value = XssFilterUtil
.stripXss("<br>select ***//||&;/*-+ <>$###@%$#@$%^#$^%$&^(&*)*\\''count or %% ..... ,,,, ");
System.out.println("type-1: '" + value + "'");
value = XssFilterUtil
.stripXss("<script src='' onerror='alert(document.cookie)'></script>");
System.out.println("type-2: '" + value + "'");
value = XssFilterUtil.stripXss("</script>");
System.out.println("type-3: '" + value + "'");
value = XssFilterUtil.stripXss(" eval(abc);");
System.out.println("type-4: '" + value + "'");
value = XssFilterUtil.stripXss(" expression(abc);");
System.out.println("type-5: '" + value + "'");
value = XssFilterUtil
.stripXss("<img src='' onerror='alert(document.cookie);'></img>");
System.out.println("type-6: '" + value + "'");
value = XssFilterUtil
.stripXss("<img src='' onerror='alert(document.cookie);'/>");
System.out.println("type-7: '" + value + "'");
value = XssFilterUtil
.stripXss("<img src='' onerror='alert(document.cookie);'>");
System.out.println("type-8: '" + value + "'");
value = XssFilterUtil
.stripXss("<script language=text/javascript>alert(document.cookie);");
System.out.println("type-9: '" + value + "'");
value = XssFilterUtil.stripXss("<script>window.location='url'");
System.out.println("type-10: '" + value + "'");
value = XssFilterUtil.stripXss(" onload='alert(\"abc\");");
System.out.println("type-11: '" + value + "'");
value = XssFilterUtil.stripXss("<img src=x<!--'<\"-->>");
System.out.println("type-12: '" + value + "'");
value = XssFilterUtil.stripXss("<=img onstop=");
System.out.println("type-13: '" + value + "'");
}
}
4.配置web.xml
<filter>
<filter-name>XSSFilter</filter-name>
<filter-class>com.data.interceptor.XSSFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>XSSFilter</filter-name>
<url-pattern>*.do</url-pattern>
</filter-mapping>本文对其增加了预防SQL盲注漏洞，将字符串中涉及到的与sql相关的关键字进行了过滤。
我是一个小菜鸟，大家如有更简单高效的代码，欢迎在评论中指出，一起分享。谢谢
参考文档：http://blog.csdn.net/catoop/article/details/50338259