QorumLogsQorumLogs08-14 09:49

XSS漏洞修复方案

基本概念及解决办法

比较典型的XSS攻击漏洞(Cascading Style Sheets, CSS),俗称跨站脚本攻击;解决办法:将特殊字符进行转义

1、增加过滤器XssFilter.java

public class XssFilter implements Filter {

    FilterConfig filterConfig = null;
    private List<String> urlExclusion = null;

    public void init(FilterConfig filterConfig) throws ServletException {
        this.filterConfig = filterConfig;
    }

    public void destroy() {
        this.filterConfig = null;
    }

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        String servletPath = httpServletRequest.getServletPath();
        if (urlExclusion != null && urlExclusion.contains(servletPath)) {
            chain.doFilter(request, response);
        } else {
            chain.doFilter(new XssHttpServletRequestWrapper((HttpServletRequest) request), response);
        }
    }

    public List<String> getUrlExclusion() {
        return urlExclusion;
    }

    public void setUrlExclusion(List<String> urlExclusion) {
        this.urlExclusion = urlExclusion;
    }
}
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {

    public XssHttpServletRequestWrapper(HttpServletRequest servletRequest) {
        super(servletRequest);
    }

    public String[] getParameterValues(String parameter) {
        String[] values = super.getParameterValues(parameter);
        if (values == null) {
            return null;
        }

        int count = values.length;
        String[] encodedValues = new String[count];
        for (int i = 0; i < count; i++) {
            encodedValues[i] = cleanXSS(values[i]);
        }
        return encodedValues;
    }

    public String getParameter(String parameter) {
        String value = super.getParameter(parameter);
        if (value == null) {
            return null;
        }
        return cleanXSS(value);
    }

    public String getHeader(String name) {
        String value = super.getHeader(name);
        if (value == null)
            return null;
        return cleanXSS(value);
    }

    private String cleanXSS(String value) {

        //You'll need to remove the spaces from the html entities below

        value = value.replaceAll("<", "& lt;").replaceAll(">", "& gt;");
        value = value.replaceAll("\\(", "& #40;").replaceAll("\\)", "& #41;");
        value = value.replaceAll("'", "& #39;");
        value = value.replaceAll("eval\\((.*)\\)", "");
        value = value.replaceAll("[\\\"\\\'][\\s]*javascript:(.*)[\\\"\\\']", "\"\"");
        value = value.replaceAll("script", "");
        return value;
    }
}

2、web.xml增加过滤器配置

<!-- xss过滤器 -->
<filter>
	<filter-name>XssFilter</filter-name>
	<filter-class>com.powersi.hygeia.web.filter.XssFilter</filter-class>
</filter>
<filter-mapping>
	<filter-name>XssFilter</filter-name>
	<url-pattern>/*</url-pattern>
</filter-mapping>

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